----------------------- Page 1----------------------PAST 10 YEAR PAPERS 2003-2012 ----------------------- Page 2----------------------Roll No. Series SHC/2 Code No. 56/2/1Please check that Code number given itten on the title page of the Please check that Please write down 8this question paper contains 8 printed pages. on the right hand side of the question paper should be wr answer-book by the candidate. this question paper contains 27 questions. the serial number of the question before attempting it.27 CHEMISTRY (Theory)Time allowed : 3 hours 70 3 General Instructions:MaximumMarks 70:(i) All questions are compulsory. (ii) Marks for each question are indicated against it. (iii) Question number 1 to 5 are very short-answer questions, carrying 1 m ark each. Answer these in one word or about one sentence each. (iv) Question number 6 to 12 are short-answer questions, carry ing 2 marks each. Answer these in about 30 words each. (v) Question number 13 to 24 are short-answer questicms of 3 marks each. Ans wer these in about 40 words each. (vi) Question number 25 to 27are long-answer questions of 5 ma rks each. Answer these in about 70 words each. (vii) Use Log Tables, if necessary. Use of calculators is not permitte(i)(ii) (iii)(iv)56/2/11P.T.O.----------------------- Page 3----------------------(v)(vi)(vii) 1. What is the coordination number in a rock salt type structure ? 12. State Raoults law for a binary solution containing volatile components. 13. What is meant by order of a reaction being zero ?14. Write the IUPAC name of the following compound : (CH ) CCH COOH 3 3 2 (IUPAC) (CH ) CCH COOH 3 3 2 5. Mention one commercial use of N,N-Dimethylaniline (DMA). N, N- (DMA)116. State as a mathematical formula the de Broglie relationship for moving parti cles. Whatexperimental evidence is available for this concept ? OR Specify s for an atom when f these values for2the ranges of values for quantum numbers ml and m electron in an the n quantum number value for it is 2. What is the significance o the orbitals ? 2n m m l s7. When can an endothermic process be spontaneous ? Give an example of such a pr ocess. 256/2/12----------------------- Page 4----------------------8. Write balanced chemical equations for the following reactions : 2 (i) (ii)(i) (ii) 9. Explain any one of the following statements : 2 (i) The transition metals are well known for the formation of interstitial compounds. (ii) The largest number of oxidation manganese in the first series of transition elements. states are exhibited by(i) (ii)10. Draw the three dimensional representations of (R)- and (S)- butan-2-ol. 2 (R)- (S)11. Write chemical reaction equations to illustrate the following reactions : 2 (i) Williamson synthesis of ethers (ii) Reimer-Tiemann reaction (i) (ii) 12. Distinguish between addition polymers and condensation polymers and give on e example of each class. 213. Answer the following in the light of MO theory : 3 (a) Which has a higher bond order, C2 or ? (b) Which species is not likely to exist, Li or Be ? 2 2 OR 56/2/1 P.T.O. ----------------------- Page 5----------------------(a) Compare the structural shapes of the following species : SF and SF 6 4 (b) What type of intermolecular forces exist between Cl and CBr present in a mutual 2 4 solution ? 3 MO (a) C2 (b) Li2 3Be2(a) SF 6 SF 4(b) Cl CBr 2 414. (a) Name an element with which silicon can be doped to give an n-type semic onductor. (b) Which type of crystals exhibits piezoelectricity ? 3 (a) (b) 15. The vapour pressure of water is 12.3 kPa at 300 K. Calculate the vapour pre ssure of a one molal solution of a non-volatile non-ionic solute in water. 3 300 K 12.3 kPa 16. Using the values of and , given herein, calculate the standard molar Gibbs energy of formation, for CS (l). Given : (CS , l) = 151.34 J K_ 1 mol_ 1, 2 2 (C, graphite) = 5.74 J K_ 1 mol_ 1, (S, JK_ 1 mol_ 1 and (CS , l) = 89.70 kJ mol_ 1. 3 2 CS2 mol_ 1, 2 (C, ) = 5.74 J K_ 1 mol_ 1, (S, ) = 31.8 JK_ 1 mol_ 1 (CS , l) = 89.70 kJ mol_ 1. 2 17. The rates of most reactions double when their temperature is raised from 29 8 K to 308 K. Calculate activation energy of such a reaction. 3 (R = 8.314 J mol_1 K_ 1, log 2 = 0.3010) 298 K 308 K (R = 8.314 J mol_1 K_ 1, log 2 = 0.3010) 56/2/1 4 (l) (CS , l) = 151.34 J K_ 1 rhombic) = 31.8 n------------------------ Page 6-----------------------18. State what is observed when (i) the electrodes connected to a battery are dipped into a sol. (ii) an electrolyte solution is added to a sol. (iii) an emulsion is subjected to high speed centrifugation. 3 (i) (ii) (iii) 19. Answer the following questions : 3 (i) Which element in the does not exhibit variable oxidation states and why ? first series of transition elements(ii) What happens when a solution of copper (II) sulphate is saturated with ammonia ? of (iii) Why do actinoids, in general, oxidation states than the lanthanoids ? (i) (ii) (II) (iii) 20. (a) Illustrate the following with an example each : (i) Linkage isomerism (ii) Coordination isomerism (b) Why is [NiCl ]2_ paramagnetic ? (Ni = 28) 3 4 (a) (i) (ii) (b) [NiCl ]2_ (Ni = 28) 4 21. Write the nuclear reactions for the following radioactive changes : 3 (i) (ii) (iii) undergoes -decy _ undergoes -decay undergoes K-decay exhibit a greater range(You can put X for the symbol which is not correctly known) 56/2/1 P.T.O. 5----------------------- Page 7-----------------------(i) (ii) (iii) X_ K-22. Explain the mechanism of nucleophilic addition to a carbonyl group and give one example of such addition reactions. 323. Write the chemical equations for the following chemical reactions : 3 (a) 1-Nitropropene is prepared from acetaldehyde (b) Benzonitrile is converted to acetophenone (c) A primary amine is prepared from a primary alkyl halide (a) (b) (c) 24. Mention one important use of each of the following : 3 (i) Equanil (ii) Sucralose (iii) Carbon fibres (i) (ii) (iii) 25. (a) Write the formulation for the galvanic cell in which the reaction, + 2+ Cu (s) + 2 Ag (aq) Cu (aq) + 2 Ag (s) takes place. Identify the cathode and the anode reactions in it. (b) Write Nernst equation and calculate the emf of the following cell : Sn (s) | Sn2+ + (0.04 M) || H (0.02 M) | H (g) (1 bar) | Pt (s) 2(Given 3) OR2,56/2/16----------------------- Page 8----------------------(a) Explain with one example each the terms weak and strong electrolytes. (b) Write the Nernst equation and calculate the emf of the following cell : 2+ + Fe (s) | Fe (0-001 M) || H (1 M) | H (g) (1 bar) | Pt (s) 2 (Given 2, 3 (a) + Cu (s) + 2 Ag (aq) 2+ Cu (aq) + 2 Ag (s) )(b) (emf) 2+ + Sn (s) | Sn (0.04 M) || H (0.02 M) | H (g) (1 bar) | Pt (s) 2(a) (b) (emf) 2+ + Fe (s) | Fe (0-001 M) || H (1 M) | H (g) (1 bar) | Pt (s) 226. (a) How would you account for any two of the following : (i) PbO is a stronger oxidising agent than SnO . 2 2 (ii) H PO acts as a monobasic acid. 3 2 (iii) The pKa value for HOCl is higher than that of HOClO.(b) Draw the structures of the following species : (i) Peroxodisulphuric acid, H S O 2 2 8 (ii) Xenon tetrafluoride, XeF4 2, 3 OR (a) Assign reasons for any two of the following observations : (i) The lower oxidation state becomes more stable with increasing atom ic number in Group 13. (ii) Hydrogen iodide is a stronger acid than hydrogen fluoride in aqueo us solution. (iii) The basic character among the hydrides of Group 15 elements decr eases with increasing atomic numbers. (b) Draw the structural formula for XeOF . 2, 3 4 56/2/1 P.T.O. ----------------------- Page 9----------------------(a) (i) SnO PbO 2 (ii) H PO 3 2 (iii) HOClO HOCl pKa (b) (i) H S O 2 2 8 (ii) XeF4 2 7(a) (i) (ii)(iii) (b) XeOF 4 27. (a) Name the three major classes of carbohydrates and give the distinctive characteristic of each class. (b) What are nucleotides ? Name two classes of nitrogen containing bases fou nd 3, 2 OR (a) Describe the classification of lipids based on their chemical compositio ns. Mention the chief chemical characteristic of each class. (b) Explain the term mutarotation. (a) (b) 3, 2 amongst nucleotides.(a) (b) 56/2/1 8----------------------- Page 10----------------------Series SHC/1 Code No. 56/1/1Roll No. n k.Candidates must write the Code o the title page of the answer-booPlease check that Code number given itten on the title page of Please check that Please write down 12 27this question paper contains 12 printed pages. on the right hand side of the question paper should be wr the answer-book by the candidate. this question paper contains 27 questions. the serial number of the question before attempting it.CHEMISTRY (Theory)Time 70 3 Generalallowed: ]3hours][ [Maximum 70Marks:Instructions:(i) All questions are compulsory. (ii) Marks for each question are indicated against it. (iii) Question number 1 to 5 are very short-answer questions, carrying 1 m ark each. Answer these in one word or about one sentence each. ing (iv) Question number 6 to 12 are short-answer 2 marks each. Answer these in about 30 words each. questions, carry(v) Question number 13 to 24 are short-answer questicms of 3 marks each. Ans wer these in about 40 words each. 56/1/1 1 [P.T.O.----------------------- Page 11----------------------rks (vi) Question number 25 to 27are each. Answer these in about 70 words each. long-answer questions of 5 ma(vii) Use Log Tables, if necessary. Use of calculators is not permitte(i) (ii) (iii)(iv)(v)(vi)(vii) 1. What is the number of atoms per unit cell in a body centered cubic structu re ? 12.Define osmotic pressure.23.For the reaction the rate law is expressed as rate What is the overall order of this reaction ?156/1/12[P.T.O.----------------------- Page 12-----------------------4.Write the IUPAC name of the compound: IUPAC15. Why do nitro compounds have high boiling points in comparison w ith other compounds of same molecular mass ? 16. eState Paulis exclusion principle. Explain giving an example how this principl limits the maximum occupancy of an energy level in an atom. OR 2ergiesState Aufbau principle and give the order of orbitals increase and hence they are filled in that order.inwhichthe 2en56/1/13[P.T.O.----------------------- Page 13----------------------7. A reaction with value greater than 1. Why ? 2 always has an equilibrium constant8.Write balanced chemical equations for the following reactions : 2 (i) Aluminium dissolves in aqueous hydrochloric acid (ii) Tin reacts with a hot alkali solution(i) (ii) 9. Write the structures of the following species: 2 (i) H PO 3 2 (ii) H SO 2 5(i) H PO 3 2(ii) H SO 2 510. Identify whether the ructural or geometrical isomers : 2 (i) (ii) 56/1/1 [P.T.O.followingpairsofcompoundsarest4----------------------- Page 14-----------------------(i) (ii) 11. How would you account for the following : (i) Phenols are much more acidic than alcohols. ose (ii) The boiling points of of the alcohols of comparable molar masses. ethers are much lower than th 2(i) (ii) 12. Draw the structure of the monomer of each of the following polymers : 2 (i) Polyvinylchloride (PVC) (ii) Nylon-6(i)(PVC)(ii) -613. Write the molecular orbital configurations of the following species and re arrange them in the increasing order of their bond lengths: 356/1/15[P.T.O.----------------------- Page 15----------------------14. Explain each of the following with a suitable example: 3 (i) Paramagnetism(ii) Piezoelectric effect (iii) Frenkel defect in crystals(i) (ii) (iii) 15. In the production of water gas the reaction involved is : 3_ 1 _ 1 For this reaction is + 134 JK mol . Find out the spontaneous feasibi lity of this reaction at (i) 25C and (ii) 1000C.+ 134 JK_ 1 mol_ 1 25C 1000C16. lene 4 ution. 2An antifreeze solution glycol (C H (OH) )ispreparedfrom222.6gofethy 2and 200 g of water. Calculate the molality of the sol If the density of this solution be , what will be the molarity of the solution ? 3 222.6 g (C H (OH) ) 200 g 2 4 217.The decomposition of NH on platinum surface, is 3 a of zero order production of N and H ? 3 2 2 [P.T.O. reaction with . What are the rates56/1/16----------------------- Page 16----------------------NH 3N H 2 218.Explain the following terms giving a suitable example in each case : 3 (i) Emulsification (ii) Homogeneous catalysis ORDefine adsorption. Write physisorption from chemisorption.anytwofeatureswhichdistinguish 3(i) (ii)19. umberHow would you account for the following ?3(i) The lower oxidation state becomes more stable with increasing atomic n in Group 13. (ii) Hydrogen fluoride is much less volatile than hydrogen chloride, (iii) Interhalogen compounds are strong oxidising agents.(i) (ii) (iii) 56/1/1 7 [P.T.O.----------------------- Page 17----------------------20. Write the name following complex compounds : 3 and draw the structure of each of the(i) (ii)(i) (ii) 21. The net nuclear reaction of a radioactive decay series is written as : 3 Write three pieces of information that you get from the above equation.22. ds :Give chemical tests to distinguish between the following pairs of compoun 3 (i) Propanal and propanone (ii) Methyl acetate and ethyl acetate (iii) Benzaldehyde and benzoic acid(i) (ii) (iii) 23. How would you achieve the following conversions : 3 (i) Nitrobenzene to aniline 56/1/1 [P.T.O. 8----------------------- Page 18----------------------(ii) An alkyl halide to a quaternary ammonium salt . (iii) Aniline to benzonitrile Write the chemical equation with reaction conditions in each case.(i) (ii)(iii)24. 3(i) Give an example of a hybrid propellant. (ii) What are acid dyes ? (iii) Name a food preservative which is most commonly used by food producers. (i) (ii) (iii) 25. (a) Describe the general trends in the following properties of the first series of the transition elements : 3 (i) Stability of +2 oxidation state (ii) Formation of oxometal ions (b) Assign reason for each of the following: 2 (i) Transition elements exhibit variable oxidation states (ii) Transition metal ions are usually coloured OR 56/1/1 .T.O. 9 [P----------------------- Page 19----------------------(a) Write the steps involved in the preparation of: (i) K Cr O from Na CrO 2 2 7 2 4 (ii) KMnO from K MnO 4 2 4 (iii) Calomel from corrosive sublimate does (b) What is meant by lanthanoid contraction ? it have on the chemistry of the elements which follow lanthanoids ? (a) (i) +2 (ii) What effect 2 3(b) (i) (ii)(a) (i) K Cr O Na CrO 2 2 7 2 4 (ii) KMnO 4 (iii) (b) 26. (a) Calculate the emf of the cell Given : 56/1/1 10 [P.T.O. 3 K MnO 2 4----------------------- Page 20----------------------(b) Explain with examples the terms weak and strong electrolytes. OR M 1 M KCl solution at 298 K is ? 3 2 (b) Predict the products of electrolysis in the following: A solution of (a) (b) with platinum electrodes. (emf) (a) The resistance of a conductivity cell containing 0.001 KC1 solution at 298 K is 1500 . What is the cell constant, if the conductivity of 0.00 2(a) 298 K 0.001 M KC1 298 K 0.001 M KCl1500 (b)27. ach(a) Name the three major classes of carbohydrates and give an example of e of these classes. (b) Answer the following: 3 2 linkage is responsible for the primary(i) What type structure of proteins ?of(ii) Name the location where protein synthesis occurs in our body. OR (a) How are lipids classified ? Give an example of each class. 56/1/1 11 3 [P.T.O.----------------------- Page 21----------------------(b) Explain the following terms : (i) Mutarotation (ii) Avitaminosis (a) (b) (i) (ii) 2(a) (b) (i) (ii) 56/1/1 12 [P.T.O.----------------------- Page 22----------------------Roll No. Series SHC Code No. 56/1Please check that this question paper contains 8 printed pages. Code number given on the right hand side of the question paper should be wr itten on the title page of the answer-book by the candidate. Please check that this question paper contains 27 questions. Please write down the serial number of the question before attempting it. 8 27 CHEMISTRY (Theory)Time allowed : 3 hours 70 3 General Instructions:MaximumMarks 70:(i) All questions are compulsory. (ii) Marks for each question are indicated against it. (iii) Question number 1 to 5 are very short-answer questions, carrying 1 m ark each. Answer these in one word or about one sentence each. (iv) Question number 6 to 12 are short-answer questions, carry ing 2 marks each. Answer these in about 30 words each. (v) Question number 13 to 24 are short-answer questicms of 3 marks each. Ans wer these in about 40 words each. (vi) Question number 25 to 27are long-answer questions of 5 ma rks each. Answer these in about 70 words each. (vii) Use Log Tables, if necessary. Use of calculators is not permitte(i) (ii) (iii)(iv)56/11P.T.O.----------------------- Page 23----------------------(v)(vi)(vii) 1. Find out the number of atoms per unit cell in a face-centred cubic structure having only single atoms at its lattice points. 12. State the condition resulting in reverse osmosis.13. Express the rate of the following reaction in terms of disappearance of hydro gen in the reaction 14. Name the following compound according to IUPAC system : (IUPAC) 5. Why do amines react as nucleophiles ? 6. (a) Write the mathematical expression wavelength of a moving particle and its momentum (p). he (b) What physical meaning absolute value of wave function, ? is OR for the relationship11 ofattributedtothesquareof 2tState the Heisenberg Uncertainty Principle and explain as to why it is not o f real consequence when applied to a macroscopic object, like a cricket ball. 2 (a) (b) (p)56/12----------------------- Page 24----------------------7. Define conductivity and molar conductivity for the solution of an electrolyt e. 28. How would you account for the following : (i) Sulphur hexafluoride is less reactive than sulphur tetrafluoride. (ii) Of the noble gases only xenon forms known chemical compounds. (i) (ii)29. On the basis of the standard electrode potential values stated for acid solu tion, predict 4+ II III whether Ti species may be used to oxidise Fe Reaction Ti4+ II Fe Fe III to Fe . 210. What are chiral objects ? Indicate of chirality, if any, in the molecules of 3-bromopent-l-ene. (Chiral)thepresenceofcentre 211. How may the following conversions be carried out : (i) Propene to propan-2-ol (ii) Anisole to phenol (Write the reaction only.) (i) (ii) 12. Write formulae of the monomers of polythene and teflon.2213. Define bond order in a diatomic molecule. Find the bond order in O molecul e. State and2 explain magnetic character of molecular oxygen. O 2 356/1 .3P.T.O----------------------- Page 25----------------------14. Assign reasons for the following : 3 (i) Phosphorus doped silicon is a semiconductor. (ii) Schottky defect lowers the density of a solid. (iii) Some of the very old glass objects appear slightly milky instead of be ing transparent. (i) (ii) (iii) 15. A 0.1539 molal aqueous solution of cane sugar has a freezing point of 271 K while the freezing point of pure water is 273.15 K. What will be the freezing point of an aqueous solution containing 5 g of glucose per 100 g of solution ? 3 271 K 273.15 K 16. Calculate the standard cell potential of the galvanic cell in which the fol lowing reaction takes place : 3 Also calculate the value of the reaction. (Given :( 17. The rate constant for a first order reaction is How much time will it take to reduce the concentration of the reactant to 1/10th of its initial value ? 318. Describe the following types of colloids, giving an example for each : 3 (i) Multimolecular colloids (ii) Macromolecular colloids OR Explain the following terms with a suitable example in each case : 3 (i) Shape-selective catalysis (ii) Dialysis 56/1 4----------------------- Page 26----------------------(i) (ii)(i) (ii) 19. How would you account for the following : 3 (i) The transition elements have high enthalpies of atomisation. (ii) The transition metals and their compounds are found to be good catalyst s in many processes.(i) (ii) 20. Describe for any two of the following complex ions, the type of hybridizatio n, shape and magnetic property : 3 (i) (ii) (iii) (At. Nos. Fe = 26, Co = 27, Ni = 28)(i) (ii) (iii) Fe = 26, Co = 27, Ni = 2821. Complete the following statements for nuclear reactions : 3 (i) (ii) (iii) (Note: You may use X as symbol if the correct symbol in a reaction is not kn own) 56/1 P.T.O. 5----------------------- Page 27-----------------------(i) (ii) (iii)X22. Write one chemical equation for each, to illustrate the following reactions : 3 (i) Rosenmund reduction (ii) Cannizzaro reaction (iii) Fischer esterification (i) (ii) (iii) 23. Account for any two of the following : (a) Amines are basic substances while amides are neutral. (b) Nitro compounds have higher boiling points than the hydrocarbons having almost the same molecular mass. (c) Aromatic amines are weaker bases than aliphatic amines. 3(a) (b)(c) 24. (a) Describe and illustrate with an example each, a mordant dye and a deterg ent, (b) Give an example of a liquid .propellant. 3 (a) (b) 25. (a) Prove that for a system which is not isolated.(b) The decomposition of Fe O is a non-spontaneous process 2 3 Show that the reduction of Fe O by CO can be made spontaneous by couplin g with 2 3 the following reaction : 2, 3 OR 56/1 6----------------------- Page 28----------------------(a) Define the following terms : (i) Entropy (ii) A spontaneous process (b) Given below are the standard Gibbs energy changes for two reactions at 1 773 K : Discuss the possibility of reducing Al O with carbon at this temperatur e. Given that : 2 3 2, 3 (a) (b) Fe O 2 3 CO Fe O 2 3(a) (i) (ii)(b) 1773 K Al O 2 3 26. (a) Assign reasons for the following : (i) PbO is a stronger oxidising agent than SnO . 2 2 (ii) In solid state PCl5 behaves as an ionic species, (iii) Aluminium chloride (A1C13) is very often used as a catalyst. (b) What is the structural difference between orthosilicates and pyrosilicat 3, 2 OR (a) Assign reasons for the following : (i) The acid strengths of acids increase in the order HF < HCl < HBr < HI (ii) The lower oxidation state becomes more stable with increasing atomi c number in Group 13. (iii) H PO behaves as a monoprotic acid. 3 2 es ? (b) Draw the structures of the following compounds : (i) SF4 (ii) XeF2 3, 2 56/1 P.T.O. ----------------------- Page 29----------------------(a) (i) SnO PbO 2 (ii) PCl 5 (iii) (b) (A1C1 ) 3 2 7(a) (i) HF < HCl < HBr < HI (ii) (iii) H PO 3 2 (b) (i) SF4 (ii) XeF2 27. (a) Answer the following questions briefly :(i) What are reducing sugars ? (ii) What is meant by denaturation of a protein ? (iii) How is oxygen replenished in our atmosphere ? (b) Define enzymes. OR (a) Answer the following questions briefly : (i) What are any two good sources of vitamin A ? (ii) What are nucleotides ? (iii) Give an example of simple lipids. (b) How are carbohydrates classified ? 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(iii) Question numbers 1 to 8 are very short-answer questions and carr y 1 mark each. (iv) Question numbers 9 to 18 are short-answer questions and carry 2 marks each. (v) ry 3 marks Question numbers 19 to 27 are also short-answer questions and car each. (vi) Question numbers 28 to 30 are long-answer questions and carry 5 m arks each. (vii) Use Log Tables, if necessary, Use of calculators is not allowed. QUESTION PAPER CODE 56/1/1 1. Crystalline solids are anisotropic in nature. What does this statement mean? 2. Express the relation between conductivity and molar conductivity of a sol ution held in a cell. 3. 4. 5. Define electrophoresis. Draw the structure of XeF molecule. 2 Write the IUPAC name of the following compound: (CH ) 3 3 6. CCH Br 2Draw the structure of 3-methylbutanal.7. Arrange the following compounds in an increasing order of their solubilit y in water: C H NH , (C H ) NH, C H NH 6 5 2 2 5 2 2 5 2 182----------------------- Page 98----------------------8. What are biodegradable polymers?9. The chemistry of corrosion of iron is essentially an electrochemical phe nomenon. Explain the reactions occurring during the corrosion of iron in the atmo sphere. o 10. Determine the values of equilibrium constant (K ) and G for the followi ng reaction: C o Ni(s) + 2Ag+ (aq) Ni2+(aq) + 2Ag(s), E .05 V 1 (IF = 96500 C mol 11. 12. . 2 3 (ii) SF is kinetically an inert substance. 6 OR State reasons for each of the following: (i) (ii) 13. All the P-Cl bonds in PCl molecule are not equivalent. 5 Sulphur has greater tendency for catenation than oxygen. ) Distinguish between rate expression and rate constant of a reaction. State reasons for each of the following: (i) The N O bond in NO is shorter than the N O bond in NO = 1Assign reasons for the following: (i) (ii) Copper (I) ion is not known in aqueous solution. Actinoids exhibit greater range of oxidation states than lanthanoids. 14. Explain the following giving one example for each: (i) (ii) 15. Reimer-Tiemann reaction. Friedel Crafts acetylation of anisole.How would you obtain (i) Picric acid (2, 4, 6-trinitrophenol) from phenol,(ii)2-Methylpropene from 2-methylpropanol ? 183----------------------- Page 99----------------------16. What is essentially the difference between -form of glucose and -form of glucose? Explain. 17. of 18. Describe what you understand by primary structure and secondary structure proteins. Mention two important uses of each of the following: (i) (ii) Bakelite Nylon 619. Silver crystallizes in face-centered cubic unit cell. Each side of this unit cell has a length of 400 pm. Calculate the radius of the silver atom. (Assume the a toms just touch each other on the diagonal across the face of the unit cell. That i s each face atom is touching the four comer atoms.) 20. Nitrogen pentoxide decomposes according to equation: 2N O (g) 2 5 4 NO (g) + O (g). 2 2 This first order reaction was allowed to proceed at 40 C and the data bel ow were collected: [N O ] (M) 2 5 0.400 0.289 0.209 0.151 0.109 (a) (b) (c) Time(min) 0.00 20.0 40.0 60.0 80.0Calculate the rate constant. Include units with your answer. What will be the concentration of N O after 100 minutes? 2 5 Calculate the initial rate of reaction.184 ----------------------- Page 100----------------------21. Explain how thephenomenon of adsorption finds application in each ofthe f ollowing processes: (i) (ii) Production of vacuum Heterogeneous catalysis(iii) Froth Floatation process OR Define each of the following terms: (i) (ii) Micelles Peptization(iii) Desorption 22. Describe the principle behind each of the following processes: (i) (ii) Vapour phase refining of a metal. Electrolytic refining of a metal.(iii) Recovery of silver after silver ore was leached with NaCN. 23. Complete the following chemical equations: 2 (i) (ii) Mn O4 KMnO4 2 (iii) Cr O4 2 24. + H S + H 2 + + + C2 O4 heated + H +Write the name, stereochemistry and magnetic behaviour of the following: (At.nos. Mn = 25, Co = 27, Ni = 28) (i) (ii) K 4 [Mn(CN) ] 6 2[Co(NH ) Cl] Cl 3 5(iii) K [Ni(CN) ] 2 4 185----------------------- Page 101----------------------25. Answer the following: (i) (ii) Haloalkanes easily dissolve in organic solvents, why? What is known as a racemic mixture? Give an example.6(iii) Of the two bromoderivatives, C H CH(CH )Br and C H CH(C H ) Br, 6 5 3 5 6 5 which one is more reactive in SN 1substitution reaction and why?26.(a) (b)Explain why an alkylamine is morebasic than ammonia. How would you convert (i) (ii) Aniline to nitrobenzene Aniline to iodobenzene ?27.Describe the following giving one example for each: (i) (ii) Detergents Food preservatives(iii) Antacids 28. (a) es a change (b) 50g of MgBr2 Differentiatebetween molarity and molality for a solution. How do in temperature influence their values? Calculate the freezingpoint of an aqueous solution containing 10. in 200 g of water. (Molar mass of MgBr = 184 g) 2 (Kf for water = 1.86 K kg mol OR (a) ssure of a (b) 0 g of NaCl , b Molar mass of NaCl = 58.44 g) 29. (a) Give chemical tests to distinguish between (i) Propanal and propanone, Define the terms osmosis and osmotic pressure. Is the osmotic pre solution a colligative property? Explain. Calculate the boiling point of a solution prepared by adding 15.0 1 to 250.0 g of water. (K for water = 0.512 K kg mol 1 )(ii)Benzaldehyde and acetophenone. 186----------------------- Page 102----------------------(b) How would you obtain (i) (ii) But-2-enal from ethanal, Butanoic acid from butanol,(iii) Benzoic acid from ethylbenzene ? OR (a) Describe the following giving linked chemical equations: (i) (ii) (b) Cannizzaro reaction DecarboxylationComplete the following chemical equations: CH CH 2 (i) KOH, heat COOH SOCl2 (ii) COOH heat H O 3 (iii) C H CONH 6 5 2 heat 3 KMnO 430.(a)Explain the following: (i) (ii) NF is an exothermic compound whereas NCl is not. 3 3 F is most reactive of all the four common halogens. 2(b)Complete the following chemical equations: (i) (ii) C + H SO 2 (conc) 4 2P + NaOH + H O 4 + F2 (excess)(iii) C12187 ----------------------- Page 103----------------------OR (a) Account for the following: (i) 3 (ii) roup 15 of the periodic table. (b) Complete the following chemical equations: (i) (ii) P + SO Cl 4 2 XeF 2 + H O 2 2 Tendency to form pentahalides decreases down the group in g The acidic strength decreases in the order HCl > H S > PH 2(iii) I2 + HNO3 (conc) QUESTION PAPER CODE 56/1 1. 2. 3. 4. 5. Define order of a reaction. 1What is meant by shape selective catalysis ? 1 Differentiate between a mineral and an ore. 1 What is meant by lanthanoid contraction ? 1 Write the IUPAC name of the following compound: 1 CH = CHCH Br 2 26. 7. 8.Draw the structure of 4-chloropentan-2-one. 1 How would you convert ethanol to ethene ? 1 Rearrange the following in an increasing order of their basic strengths: 1 C H NH , C H N(CH ) , (C H ) NH and CH NH . 6 5 2 6 5 3 2 6 5 2 3 29. knowExplain how you can determine the atomic mass of an unknown metal if you its mass density and the dimensions of unit cell of its crystal. 2 188----------------------- Page 104----------------------10. Calculate the packing efficiency of a metal crystal for a simple cubic l attice. 2 11. State the following: 2 (i) (ii) Raoults law in its general form in reference to solutions. Henrys law about partial pressure of a gas in a mixture.12. What do you understand by the rate law and rate constant of a reaction? I dentify the order of a reaction if the units of its rate constant are: 2 1 (i) (ii) L L mol mol s 1 1 s 113. The thermal decomposition of HCO H is a first order reaction with a rate constant 2 3 1 of 2.4 x 10 s at a certain temperature. Calculate how long will it take for threefourths of initial quantity of HCO H to decompose. (log 0.25 = 0.6021) 2 2 14. Describe the principle controlling each of the following processes: 2 (i) (ii) 15. Vapour phase refining of titanium metal Froth floatation method of concentration of a sulphide ore.How would you account for the following: 2+ 4 is reducing in nature while with the same d-orbital configu(i) ration (d )CrMn3+ is an oxidising agent. (ii) In a transition series of metals, the metal which exhibits the gr eatest number of oxidation states occurs in the middle of the senes. 16. Complete the following chemical equations:2 2 (i) (ii) MnO4 Cr O2 2 7 (aq) + S O3 2 (aq) + H O (l) 2(aq) + Fe2+ (aq) + H + (aq) ORState reasons for the following: 2 (i) Cu (I) ion is not stable in an aqueous solution. 189 ----------------------- Page 105----------------------(ii) 3d series of table cationic species. 17. Explain what is meant by the following: 2 (i) (ii) 18. es, peptide linkage pyranose structure of glucose Unlike Cr3+, Mn3+, Fe3+ and the subsequent other M3+ ions of the elements, the 4d and the 5d series metals generally do not form sWrite the main structural difference between DNA and RNA. Of the four bas name those which are common to both DNA and RNA. 219. A solution prepared by dissolving 8.95 mg of a gene fragment in 35.0 mL. of water has an osmotic pressure of 0.335 torr at 25 C.Assuming that the gene fragm ent is a non-electrolyte, calculate its molar mass. 3 20. Classify colloids where the dispersion medium is water. State their char acteristics and write an example of each of these classes. 3 OR Explain what is observed when (i) (ii) an electric current is passed through a sol a beam of light is passed through a sol(iii) an electrolyte (say NaCl) is added to ferric hydroxide sol3 21. How would you account for the following: 3 (i) (ii) . 2 3 (iii) Both O2 and F2 stabilize high oxidation states but the ability o f oxygen to stabilize the higher oxidation state exceeds that of fluorine. 22. Explain the following terms giving a suitable example in each case: 3 (i) (ii) Ambident ligand Denticity of a ligand H S is more acidic than H O. 2 The N O bond in NO 2 is shorter than the N O bond in NO(iii) Crystal field splitting in an octahedral field 190 ----------------------- Page 106----------------------23. Rearrange the compounds of each of the following sets in order of reactiv ity towards S 2 displacement: 3 N (i) (ii) (iii) 24. 2-Bromo-2-methylbutane, 1-Bromopentane, 2-Bromopentane 1- Bromo-3-methylbutane, 2-Bromo-2-methylbutane, 3- Bromo-2-methylbutane 1- Bromobutane, 1- Bromo-2,2-dimethylpropane, 1- Bromo-2-methylbutaneHow would you obtain the following: (i) (ii) (iii) Benzoquinone from phenol 2-Methylpropan-2-ol from methylmagnesium bromide Propan-2-ol from propene25.State reasons for the following: 3 (i) (ii) pKb value for aniline is more than that for methylamine. Ethylamine is soluble in water whereas aniline is not soluble inwater.(iii) 26.Primary amineshave higher boiling pointsthan tertiary amines.Draw the structures of the monomers of the following polymers: 3 (i) (ii) (iii) Polythene PVC Teflon27.What are the following substances? Give one example of each. 3 (i) (ii) Food preservatives Synthetic detergents(iii) Antacids 28. (a) d cathode of a lead storage battery. 191 ----------------------- Page 107----------------------(b) 1.0 x 10 Calculate the potential for half-cell containing 3+ 4 + 0.10 M K Cr O M H (aq) 2 (aq), 0.20 M Cr 2 7 (aq) and What type of a battery is lead storage battery? Write the anode an reactions and the overall cell reaction occurring in the operationThe half-cell reaction is Cr O2 (l), 2 2 o = 1.33 V. and the standard electrode potential is given as E 5 OR (a) M Hg(NO ) solution with a current of 2.00 A for 3 hours? 3 2 1 [Hg(NO ) = 200.6 g mol 3 2 ] How many moles of mercury will be produced by electrolysing 1.0 7 (aq) + 14 H+ (aq) + 6 e 2 Cr3+ (aq) + 7 H O(b) A1 urs when theo 3+ A voltaic cell is set up at 25 C with the following half-cells (0.001 M) 2+ and Ni (0.50 M). Write an equation for the reaction that occ cell generates an electric current and determine the cell potential. (Given: Eo 2 Ni / Ni 29. (a) = 0.25 V, Eo 5 3 Al / Al = 1.66 V)V)Draw the structures of the following molecules: (i) (ii) (HPO ) 3 3 BrF3(b)Complete the following chemical equations: (i) (ii) (iii) HgCl + PH 2 S0 3 XeF 4 + H SO 2 + H O 5 2 OR 4 3(a) on of NaOH ?What happens when (i) (ii) chlorine gas is passed through a hot concentrated soluti sulphur dioxide gas is passed through an aqueous solutio salt ? 192n of a Fe (III)----------------------- Page 108----------------------(b) Answer the following: (i) What is the basicity of H PO and why.? 3 3(ii) Why does fluorine not play the role of a central atom in inte rhalogen compounds? (iii) Why do noble gases have very low boiling points? 530.(a)Illustrate the following name reactions: (i) Cannizzaros reaction(ii) Clemmensen reduction (b) How would you obtain the following: (i) But-2-enal from ethanal(ii) Butanoic acid from butanol (iii) Benzoic acid from ethylbenzene 5 OR (a) Give chemical tests to distinguish between the following: (i) Benzoic acid and ethyl benzoate(ii) Benzaldehyde and acetophenone (b) Complete each synthesisby giving missingreagents or products in the following: COOH SOCl2 (i) COOH (ii) C H CHO 6 5 (iii) 5 193 ----------------------- Page 109----------------------Marking Scheme Chemistry General Instructions 1. The Marking Scheme provides general guidelinesto reduce subjectivity in the marking. The answers given in the Marking Scheme are suggested answers. The c ontent is thus indicative. If a student has given any other answer which is differe nt from the one given in the Marking Scheme, but conveys the same meaning, such answers sh ould be given full weightage. 2. The Marking Scheme carries only suggested value point for the answer s. These are only guidelines and do not constitute the complete answers. The stud ents can have CH2 heat H 2 NCONHNH 2 CHOtheir own expression and if the expression is correct the marks, wil l be awarded accordingly. 3. The Head-Examiners have to go through the first five answer-scripts evaluated by each evaluator to ensure that the evaluation has been carried out as per the instruction given in the marking scheme. The remaining answer scripts meant for evaluation shall be given only after ensuring that there isno significant variation i n themarking of individual evaluators. 4. Evaluation is to be done as per instructions provided in the Marking Scheme. It should not be done according to ones own interpretation or any other consi deration - Marking Scheme should be strictly adhered to and religiously followed. 5. If a question has parts, please award marks in the right hand side f or each part. Marks awarded for different parts of the question should then be totalled up and written in the left hand margin and circled. 6. If a question does not have any parts, marks be awarded in the lefthand margin. 7. If a candidate has attempted an extra question, marks obtained in th e question attempted first should be retained and the other answer should be scored out. 8. No Marks to be deducted for the cumulative effect of an error. It sh ould be penalized only once. 9. A full scale of marks 0-70 has to be used. Please do not hesitate to award full marks if the answer deserves it. 10. Separate marking schemes for all the three sets have been provided. 194 ----------------------- Page 110----------------------QUESTION PAPER CODE 56/ 1/1 EXPECTEDANSWERS/VALUE POINTS 1 It means that some of their physical properties show different values whe n measured along different directions in the same crystal. 1 2 m = / c 1where m is molar conductivity, is conductivity, c is concentration in mo l L1 3 The movement of colloidal particles under an applied electric potential t owards oppositely charged electrodes is called electrophoresis. 1 4 5 6 1-bromo-2, 2 - dimethyl propane 1 CH 3 | CH 3 7 C H NH 6 5 < (C H ) NH < C H NH 1 2 2 5 2 2 5 -CH -CH -CHO 1 228 Polymers which undergo bacterial degradation in the environment and are t hus ecofriendly. 1 9 oxidation: Fe (s) Fe2+ (aq) + 2e+ 1 Reduction: O 2 195 ----------------------- Page 111----------------------1 + Atmospheric oxidation: 2Fe2+ (aq) + 2H O(l) + Fe O (s) + 4H (aq) 2 2 10 rG 3 0 = -n FE cell = -2 x (96500Cmor11) x 1.05V 1 1 = -202650J mol1 or -202.6kJ mor 0 nE 0 2 O (g) 2 (g) + 4H+ (aq) + 4clog Kc = 0.0591 2 x 1.05V = 0.0591 = 35.53 35 K c [Marks to be given if substitution is done with proper units] 11 Rate Law is the expression in which reaction rate is given in terms of mo lar con1 centration of reactants with each term raised to some power which may or may not be same as the stoichiometric coeffcient of the reacting species in a balanced chemical equation, whereas the rate constant is defined as the rate of re action when the concentration of the reactant(s) is unity. 1 (or properly explained in any other way) 12 i) are sharing 2 a double bond while in NO3 , 3 bonds are sharing a double bond wh ich means that bond in NO will be shorter than in NO 2 Or In NO , bond order is 1.5while in NO s 1.33 2 3 ii) Because SF is sterically protected by six F atoms / co-ordinativ ely saturated. 6 OR i) P-Cl bonds Because PCl has a trigonal bipyramidal structure in which three 5 , bond order i . 3 = 3.412 x 10 1In the resonance structure of these two species, in NO , 2 bondsare equatorial and two P-Cl bonds are axial. 1+1 ii) Because S-S single bond is stronger than O-O single bond 196 ----------------------- Page 112----------------------13 i) , disBecause copper(I) ion is unstable in aqueous solution and undergoes proportionation. 1+1 ii) ds. 14 (i) OH OH + H CHCl CHO 3 + aq NaOH 2 NaOH 2 Reimer-Tiemann Reaction ONa+ CHCl ONa+ CHO Because of comparable energies of Sf; 6d and 7s orbitals in actinoiInternediate Salicylaldehyde (or any other example) ii) OCH OCH 3 3 anhydrous AICI 3 + CH COCl + 3 COCH 3 (or any other example) 15 i) OH NO conc HNO 3 2 NO2 OH COCH3 Friedal-Crafts acetylation of anisole OCH 3NO 2 (or by action of conc.HNO on phenol) 3 (ii) (or by action of hot conc. H SO ) 2 4 16 - form of glucose and - form of glucose differ only in the configuratio n of the hydroxyl group at C in cvclic structure of glucose/hemiacetal form of glu cose/ 1 pyranose structure of glucose. (or structure drawn) 2 197 ----------------------- Page 113----------------------17 Primary structure of proteins:The protein in which amino acids are linked with each other in a specific sequence is said to be the primary structure of that protein. 1 Secondary structure of proteins: It refers to the shape in which a long polypeptide chain can exist i.e. - helix and -pleated structure. 1 18 i) Bakelite For making combs, electrical switches, handles of utensils, comput er discs (or any other use) any two + ii) Nylon-6 For making tyre cords, fabrics, ropes(or any other use) any two + 19 For fcc unit cell a r 1 2 2 Given a = 400 pmr = 400 / 22 pm r = 141.4 pm 1 20 a) k = 2.303 log [A ] 0 t k = 2.303 20 min k = 0.0163min1 1 b) k = 2.303 log [A ] 0 t [A] [A] log 0.400 0.2890.0163 = 2.303 log 0.400 100 [ A] [A] = 0.078M 1 c) Initial rate R = k [N O ] 2 5 1 = 0.0163 min (0.400 M) = 0.00652 M min1 1 198 ----------------------- Page 114----------------------21 el to create a vacuum. ii) ases the rate of reaction. iii) Froth floatation process: In this process, sulphide ore is concentrated by using pine oil whi ch adsorbs the ore particles and imurities are wetted by water which settle at Heterogeneous catalysis: Adsorption of reactants on the solid surface of the catalysts incre i) Production of vacuum: The remaining traces of air can be adsorbed by charcoal from a vessthe bottom.1x3 = 3 ORi) highMicelles: Micelles are associated colloids which show colloidal behaviour at concentration and act as strong electrolytes at low concentration.ii) ng it withPeptization: The process of converting a precipitate into colloidal sol by shaki dispersion medium in the presence of a small amount of electrolyteis called Peptization. iii) Desorption: The process of removing an adsorbed substance from a surface on whi ch it is adsorbed is called desorption. 1x3 = 3 22 i) Vapour phase refining of a metal: 1 In this method the metal is converted into its volatile compound wh ich is then decomposed to give pure metal. ii) Electrolytic refiniing of a metal: 1 In this method, the impure metal is made to act as anode and metal in pure form is used as cathode. They are put in a suitable electrolytic ba th containing soluble salt of the same metal. The more basic metal goes to the an ode and the less basic metal gets deposited at the cathode. 199 ----------------------- Page 115----------------------iii) and silver Recovery of silver after silver ore was leached with NaCN: More basic and cheaper zinc can displace silver from the complex 1 metal can be recovered. 2 2 [Ag(CN) ] + 2Ag(s) 2 4 (aq) 23 i) 5C O 2 + 2MnO 1 + 16H 2 4 2 heat ii) 2KMnO 4 iii) Cr O 2 + 3H S + 8H 2 7 24 i) K 4 2 K MnO 1 2 + 2Cr 1 4 3+ + 3S + 7H O 2 2 2 + MnO + O 4 2 4 2Mn2+ + 8H O + 10CO (aq) + Zn(s) [Zn (CN) ][Mn(CN) ] : Potassium hexacyanomanganate (II), Octahedral / 2paramagnetic. ii) octahederal/ [Co(NH ) Cl] Cl 3 5 diamagnetic. iii) iamagnetic. K [Ni(CN) ):potassium tetracyanonickelate(II), square planar / d +=1 2 4 2 :pentaamminechloridocobalt(III) chloride,( mark for the nomenclature and mark for the property in each part) 25 (i) nd solvent ting ones in the molecules. 1 (ii) wn as a racemic mixture. e.g. (+) butan-2-ol (or any other example) +=1 (iii) 26 a) kylamine is C H CH(C H ) Br, because it forms more stable carbocation. 6 5 6 5 Due to +1effect / electron donating character of alkyl group, al A mixture containing two enantiomers in equal proportions is kno Because the new intermolecular attractions between haloalkanes a molecules have about the same strength or stronger than the exismore basic than ammonia. 1 b) i) 1 ii) 1 200 ----------------------- Page 116----------------------27 (i) enzene sulDetergents are sodium salts of long chain alkyl sulphonates or b phonates. eg: Sodium Lauryl sulphate. +=1 (ii) food due mple) (iii) id in the example0 28 a) kg) of the nt in one rature. ion. of temperature because volume depends on temperature and the mass d oes not or Molarity decreases with increase of temperature. 1 0 b) T = 7.5 C f T = iK m f 0 T 0 f 0kg 0 0 C-T = 1.59 C 0 f 184 gmol-1 20 f 1 0 - T = 3 x 1.86 C kg mol 2 x 10.50g x 100 litre (or one cubic decimeter) of solution at a particular tempe 1 Molality is independent of temperature whereas Molarity is funct to microbial growth. eg: sodium benzoate, vinegar (or anyone exa +=1 Antacids: are the drugs used to prevent the overproduction of ac stomach. e.g. Sodium hydrogen carbonate / or any other suitable +=1 Molality (m) is the number of moles of the solute per kilogram ( solvent whereas Molarity is the number of moles of solute prese Food preservatives: are the compounds which prevent spoilage off 0 T = l.59 C f OR a) The flow of solvent motecutes from solution of low concentration to higher concentration through semipermeable membrane is called osmosis. The hydrostatic pressure that has to be applied on the solution to prevent the entry of the solvent into the solution through the semipermeable membrane is called the Osmotic Pressure. Yes osmotic pressure is a colligative property as it depends upo n the number of particles of the solute in a solution. 1 b) T b 1000 b 250kg T -373 K = 1.05 K b 0 T b 201 ----------------------- Page 117----------------------29 de on a water bath With. Propanal (CH CH CHO) :No yellow ppt is formed with 3 2 Propanone (CH COCH ) :Yellow crystals of Iodoform are formed. 3 3 (a) (i) Propanal and Propanone = 374.05K or 101.05 C 1 b 58.44 gmol1 = iK m b 15 g 2 x or 271.41 K 1T - T 0 = 2 x 0.512K kg mol1 xIodof orm lest. Warm each compound with iodine and sodium hydroxi(Other relevant test can be accep ted) (ii) ion. med 6 5 3 with Benzaldehyde does not respond to this test. (Other relevent test can be accepted) (b) i) ii) iii) (Or by any other suitable method) 1x3=3 OR i) om, undergo self oxidation and reduction reaction on treament with c oncentrated alkali 1 202 ----------------------- Page 118----------------------(or any other correct equation) ii) arbons when their sodium salts are heated with sodalime. The reaction is k nown as decarboxylation. 1 R-COONa NaOH, CaO Heat (Note:Award full marks for correct chemical equation; award mark if only statement is written) COO K b) (i) + R-H + Na CO 2 3 Decarboxylation:Carboxylic acids lose carbon dioxide to form hydroc Cannizzaro reaction:Aldehydes which do not have an a-hydrogen at Benzaldehyde and ActopbenoneIodof orm test. Warm each organic compound with I2 and NaOH solut 1+ 1=2 Acetophenone (C H COCH ) Yellow precipitates of iodoform are forCOCI (ii) 1x3=3 COCI (iii) C H COOH 6 5 30 (a) and N-F bo 2i) Becuase bond energy of F is lower than that of Cl nd is smaller 2 & stronger than N-Cl bond. 1 ii) b) i) ii) iii) P 4 Cl + 3F 2 2 2C 1F 1x3=3 3 203 ----------------------- Page 119----------------------OR i) o H-P C+2H SO (conc) CO 2 4 + 3NaOH + 3H O PH 2 3 + 2SO 2 2 + 3NaH PO 2 2 + 2H O 2 Because of low bond dissociation enthalpy of F-F bond. 1Because of increase in bond dissociation enthalpy from H-Cl bond t bond / Because of decrease in electronegativity from to Cl to P.ii) Because of the energy factor (inert pair effect) , stability of + 3 oxidation state increases than that of +5 oxidation state. b) i) P + 10SO Cl 2 2 2 or P + 8SO Cl 4 2 ii) 4PCl 2 3 + 4SO + 2S Cl 2 2 2 4PCl 1 + 1 5 + 10SO 2XeF 2H O 2Xe + 4HF +O 1x3=32 iii)2 32 + 10 NO 2 QUESTION PAPER CODE 56/1 EXPECTEDANSWERS/VALUE POINTS + 4H O 2I + 10 HNO (conc) 2HIO 2 31The sum of powers of the concentration terms of the reactants in the rate law expression is called the order of that chemical reaction. 1 Or P rate = k[A] [B] qOrder of reaction = P+q 2 The catalytic reaction in which the pore structure of the catalyst and th e size of the reactant and product molecules are comparable. 1 3 The naturally occurring chemical substances which occur in the earths cr ust and are obtainable by mining are called minerals, while the mineral from which th e element is extracted economically is called an ore. 1 4 The regular decrease in the atomic and ionic radii / (having the same cha rge ) of Lathanoids with increasing atomic number is known as Lanthanoid contracti on. 1 5 6 3-Bromoprop-I-ene / 3-Bromopropene 1 CH3 CO - CH2 - CH(Cl)-CH3 1 204 ----------------------- Page 120----------------------H SO 2 7 CH CH OH CH = CH 1 3 2 443K 8 (C H ) NH < C H NH 1 6 5 2 6 5 2 6 5 3 2 3 2 < C H N(CH ) < CH NH 2 2 2 4 + H O9We can determine the atomic mass of an unknown by using the formula. M= d x a3 x NA 1 Z By knowing d, a, NA & Z We can calculate the M Where d = density of the element NA =Avogadro number 1 a = cell edge or edge length Z = no. of atoms present in one unit cell.10Packing efficiency Z x volume of one atom 1 = Volume of cubic unit cell 1 x 4/3 r3 = 3 a For simple cubic lattice a= 2r Therefore packing effieciency = 8r3 = 0.524 or 52.4% 1 1x 4/3 r311 i) Raoults law states that for a solution of volatile liquids, the p artial vapour pressure of each component in the solution is directly proprtional to its mole fraction. 1 ii) Henrys law states that at a constant temperature, the solubility of a gas in a liquid is directly proportional to the pressure of the gas over th e solution. 1 205 ----------------------- Page 121----------------------12 The representation of rate of reaction in terms of concentration of the reactants isknown as rate law. x4 = 2 The rate constant is defined asthe rate of reaction when the concentrati on of reactants is unity. i) ii) 13 zero order second ordert = 2.303 x log [A]0 k [A] t = 2.303 2.4x 10 2.303 t = 2.4x 10 2.303 t = 2.4x 10 t = 578s 1 3 1 s 3 1 s x 0.60212 3 1 s x log 4 x log [A]0 [A ] /4 014 (i) In this method the titanium metal is heated with I to form a vol atile compound 2 TiI which on further heating at higher temperature decomposes to give pure 4 titanium metal. (or explanation by chemical equations) 1 (ii) de ores is ter. 3 15 (i) Cr latter having is reducing as its configuration changes from d to d , the 3+ 5 half filled t2g level whereas Mn filled orbitals (d ) 1 ii) to Mn 2+ results in half This method is based upon the fact that the surface of the sulphi preferentially wetted by oil while that of gangue is wetted by wa 1 2+ 4In atransition metal seriesthe oxidation state first increases and then decreases; At the middle it is maximum due to greater number of unpaired ele ctron in (n-l)d and ns orbitals. 1 16 (i) 8MnO4 (aq) + 3S O 2 (aq) + H O (1) 8 MnO 6 SO 2 (aq) + 20H (aq) 1 2 3 2 4 ii) ) + 7H O (1)(s) + 2+ Cr O 2 (aq) + 14 H (aq) + 6 Fe+2 (aq) 2 Cr3 (aq) + 6 Fe+3 (aq 1 2 7 2 ORi) es dispro-Because Copper(I) ion is unstable in aqueous solution and undergo portionation. 206----------------------- Page 122----------------------ii) ot occur. 17 (i) Peptide linkage:A link between two amino acids with loss of water / CO - NH 1 (ii) ructure in The six membered cyclic structure of glucose is called pyranose st analogy with pyran heterocyclic compound / or structure. 1 18 e In DNA, sugar is Deoxyribose while in RNA, it is ribose./ DNA is as doubl stranded while RNA is single stranded.(any one) 1 The common bases present in both are adenine, cytosine & guanine. 1 19 = CRT 1 w R T 2 M = 2 M = V 3 8.95x 10 g x 0.0821L atm mol 1 1 1 K x 298 K x 760 x 1000 Due to lanthanoid contraction the expected increase in size does n2 0.335 atm x 35 L 1 M2 = 14193.3 g mol 20 They are of two types i) Hydrophilic + The hydrophile sol is more stable and reversible while hydrophobic sol is less stable and is irreversible. 1 Hydrophilic sol e.g. Starch, gum, gelatin etc. (anyone) Hydrobhobic sol e.g metal sulphide, metal hydroxide (anyone) 1 OR i) te electrodes due to attraction. ii) oidal particles. iii) 21 i) O bond. / Coagulation takes place (due to neutralisation of charges.) 1x3= 3 Because bond dissociation enthalpy of H-S bond is lower that of Hoxygen is more electronegative than S. 207 ----------------------- Page 123---------------------- ii) s are sharing hich means that bond in NO 2 Or iii) ause of the tendency of oxygen to form multiple bonds with metal. In NO2 , bond order is 1.5while in NO3 , bond order is 1.33 Bec will be shorter than in NO 3 . In the resonance structure of these two species, in NO2 , 2 bond a double bond while in NO3 , 3 bonds are sharing a double bond w Tyndall effect will be observed due to scattering of light by coll Electrophoresis takes place when sol particles move towards opposi ii) hydrophobic 4 or 1.42x10 g mol 1 11x3 = 3 22 i) Ambident ligand: a unidentate ligand which can co-ordinate to th e central metal atom through more than one co-ordinating bond.e.g. NO2 , SCN 1ii) The number of donor atoms in ligating groups is known as dentici ty of that ligand. 2 e.g. in C O denticity is 2 (or any other example) 1 2 4 iii) Crystal field splitting in an Octahedral field: The splitting of d-orbitals under the influence of approaching ligand is known as crystal field splitt ing for example for 4 d , configuration is t 3e 1 / or diagrammatic representatio n. 1 2g g 23 methyl butane 1 iii) propane 1- Bromobutane > 1-Bromo- 2-methyl butane> 1-Bromo-2, 2-dimethyl 1 OH Na Cr O 2 2 7 24 (i) H SO 2 4 O OH (i) CH COCH 3 3 (ii) CH Mg Br 3 CH3 (ii) H O 2 CH 3 (i) H O/H 2 H (iii) 3 CH CH = CH 3 CH CH C C CH3 O i) ii) 1-Bromopentane > 2-Bromopentane > 2-Bromo -2-methyle butane. 1- Bromo-2 - methyl butane> 3-Bromo- 2-methyl butane> 2-Bromo-2-32 OH(or by any other suitable method.) 1x3 = 3 208 ----------------------- Page 124----------------------25 (i) its pKb creases on N which decreases its pK . b (ii) le in water d thus is insoluble. (iii) Due to hydrogen bonding in primary amines, they have higher boili ng points whereas there is no hydrogen bonding in tertiary amines. 1x3=3 26 i) CH = CH 1 2 ii) CH = CHCI 1 2 iii) CF = CF 1 2 27 (i) ood due ) (ii) ates or 2 Food preservatives: are the compounds which prevent spoilage of f to microbial growth. eg:sodiumbenzoate,vinegar (or anyone example + Synthetic detergents are sodium salts of long chain alkyl sulphon + benzene sulphonates. eg: Sodium Lauryl sulphate. 2 Due to formation of hydrogen bond with water ethyl amine is solub whereas due to bulky phenyl group aniline does not form H-bond an Due to resonance in aniline, N acquires + charge which increases whereas due to electron donating methyl group electron density in(iii) Antacids: are the drugs used to prevent the overproduction of aci d in the stomach. e,g, Sodium hydrogencarbonate. + 28 a) It is secondary cell 2 Anode Reaction: - Pb + SO PbSO (s) + 2e 4 + Cathode. Reaction: - PbO O + 2H O 4 2 2 Net reaction:+ 2H O 4 2 o b) Ecell = E cell n 1 2 7 0.0591 Ecell = 1.33 V 6 1 = 1.33V - 0.55V = 0.78V OR 209 ----------------------- Page 125----------------------a) m = Zlt M x I x t m = nF M m = 2 x 96500 Cmol m = 0.112 mol x M 0.112mol x M no. of moles of mercury = M = 0.112 mol 2+ b) 2Al+3Ni 2Al 3+ + 3Ni 1 x 2A x 3 x 60 x 60 s log (0.20)2 4 14 (0.10)( 10 ) 0.0591 log 2 [Cr3+] 2 + 14 [ Cr O ][H ] Pb + PbO 2 + 2SO 4 + 4H + 2PbSO 2 4 + 4H + SO 4 2 + 2e PbSo o o E cell = E Cathode- E anode = [-0.25 V- (-1.66 V)] = 1.41 Vo E = 1.41 V cell 2+ Nernst equation: 2Al+3Ni 1 0.059 E cell = Eo cell n 0.059 log E cell 6 0.059 = 1.41 V 6 = 1.41 V+ 0.050 V = 1.46 V (a) ii) 210 ----------------------- Page 126----------------------b) i) ii) iii) 3HgCl + 2PH 2 SO 3 6 XeF 4 + H SO 2 4 3 Hg P + 6HCl 3 2 2 2 7 + 24HF + 3O 2 OR a) i) 3Cl 2 ii) 2Fe3+ + SO + 2H O 2Fe2+ + SO 2 2 + 6NaOH 5NaCl + NaClO 3 2 + 4H 4 +3H O 2 + [-5.097] log (10 ) (0.50 M) 4 = 1.41 V 3 1 log [Ni 2+ 3 ] 2 ( 0.001 M) 2Al n=6 electrons [Al3+]2 3+ + 3NiH S O+ 12H O 4Xe + 2XeO 2b)i) ii) iii)Two, due to presence of two P-OH bonds. Due to high electronegativity of fluorine. There are no interatomic forces except weak dispersion forces. 30 a) i) reament with concentrated alkali (or any other correct equation) ii) is reduced to CH group on treatment with zinc amalgam and concentrat ed 2 HCI 1+1 211 ----------------------- Page 127----------------------b) i) ii) iii) 1x3 = 3 (Or by any other suitable method) OR (i) Benzoic acid and ethyl benzoate 3 Bezoic acid gives brisk effervesence of CO gas whereas ethyl benzoate does not 2 respond to this test (Other relevant test can be accep ted) (ii) Benzaldehyde and Actophenone Clemmensen reduction: The carbonyl group of aldehydes and ketones Cannizzaro reaction:Aldehydes which do not have an -hydrogen atom, uhdergo self oxidation and reduction reaction on tSodium bicarbonate test. Warm each compound with NaHCO ,Iodoform test: Warm each organic compound with I2 and NaOH solution. with 1+1 Acetophenone (C H COCH ) Yellow precipitates of iodoform is formed white6 53Benzaldehyde does not respond to this test. (Other relevent test can be accepted) COCl b) (i) COCl (ii) C H CH = NNHCONH 6 5 iii) a) B H . H O /OH 2 6 2 2 b) PCC 212 ----------------------- Page 128--------------------------------------------- Page 129--------------------------------------------- Page 130--------------------------------------------- Page 131--------------------------------------------- Page 132--------------------------------------------- Page 133--------------------------------------------- Page 134--------------------------------------------- Page 135--------------------------------------------- Page 136--------------------------------------------- Page 137--------------------------------------------- Page 138--------------------------------------------- Page 139----------------------CHEMISTRY2003 (Set IDelhi) 2Q. 1. Write all the four quantum numbers of the electron in the outermost shell of rubidium (At. no. = 37) atom.1Q. 2. What type of hybridization is associated with N in NH 3 ? What is the expe cted bond angle in NH ? 1 3 Q. 3. Mention one property which is caused due to the presence of F-centre in a solid. Q. 4. Write Nernst equation for single electrode potential. 1 Q. 5. Complete the nuclear equation: 1 Q. 6. How does chemical adsorption of a gas on a solid vary with temperature? 1 Q. 7. Mention the chief reason for the anomalous behaviour of lithium in Group o f the periodic table. 1 Q. 8. Why is the third ionization energy of manganese (At. no. =25) unexpectedly high? 1 Q. 9. Write IUPAC name of the complex Na [Cr (OH) F ]. 1 3 Q. 10. Mention two main functions of lipids. 1 Q. 11. Calculate the wavelength of an electron that has been accelerated in a pa rticle accelerator through a potential difference of 100 million volts. 2 -19 (1 eV= 1.6 x 10 J, m = 9.1 x 10 e -31 kg, h= 6.6 x 10 -34 Js. 2 4Q. 12. Caesiurn chloride crystallises as a body centred cubic lattice and has a density of 4.0 g cm -3 . Calculate the length of the edge of the unit cell of caesium chloride crystal. 2 -1 1 [Molar mass of CsCI = 168.5 g mol ] Q. te Q. he , Na = 6.02 x 10 23 mol -13. What are non-ideal solutions? Explain as to why non-ideal solutions devia from Raoults law. 2 14. The standard free energy change for a reaction is -212.3 kJ mol -1 . If t enthaply of the reaction is - 216.7 kJ mol - 1 ,calculate the entropy change for the reaction. 2 Q. 15. The rate constant of a reaction is t. Calculate the value of activation energy, E a for the rection.Q. 16. What are photochemical reactions? Explain the machanism of the photo- che mical reaction occurring between hydrogen and chlorine gas. 2 Q. 17. One milligram of 90Sr was absorbed by a new-born child. How much of 90Sr will remain in his bones after 20 years? The half-life of 90Sr is 28.1 years. 2 Q. 18. How are the following sole produced: 2 (a) Sulphur sol (b) Collodion Q. 19. Write IUPAC names of the following: 2 (i) (ii) CH - NH - CH -CH - CH 3 2 3----------------------- Page 140----------------------Q. 20. Write one reaction each to exemplify the following: (a) Aldol condensation (b) Friedel-Crafts reaction Q. 21. How do you account for the following: 2 (a) All scandium salts are white. (At. No. of Sc = 21) (b) The first ionization energies of the 5d transition elements are higher than those of the 3d and 4d transition elements in respective groups. Q. 22. Using the valence bond approach, deduce the shape and magnetic character of 2 Q. 23. What are elastomers? Write the chemical equation to represent the prepara tion ration of Buna-S. 2 Q. 24. Name the chemical components which constitute nucleotides. Write any two functions of nucleotides in a cell. 2 Q. 25. What are hormones? State the function of the following hormones: 2 (a) Testosterone (b) Oxytocin Q. 26. Give one important use of each of the following: 2 (i) Bithional (ii) Chloramphenicol(iii) Streptomycin (iv) Paracetamol Q. 27. Explain as to why there is a rise in boiling point when a non-volatile so lid is dissolved in a liquid. 0 0.90 g of a non-electrolyte was dissolved in 87.90 g of benzene. This raised the boiling point of benzene by 0.25 C. If the molecular mass of the non-electrolyte is 103.0 g mol -1 , calculate the molal el evation constant for benzene. 3 Q. 28. State the law of thermodynamics that was first formulated by Nernst in 19 06. What is the utility of this law? The equilibrium constant for the reaction Calculate the value of for the reaction.Predict the feasibility of the reaction under standard states. 3 Q. 29. Calculate the cell emf at 25 C for the following cell:Calculate the maximum work that can be accomplished by the operation of this cel l. 3 Q. 30. Write reactions and conditions for the following conversions: 3 (i) Chloroform into diethylcarbonate (ii) Phenol into salicylic acid (iii) 2-propanone into 2-inethyl-2 -propano Q. 31. Write chemical tests to distinguish between: 3 (i) Phenol and Benzoic acid (ii) Propanal and propanone (iii) Formic acid and Acetic acid Q. 32. (a) Starting from a sample of chromite ore, how is potassium dichromate p repared? Describe all the steps involved with chemical equations. ----------------------- Page 141----------------------(b) Write the balanced chemical equation for the reaction between an acidified s olution of potassium dichromate and potassiumiodide. 3 Q. 33. (a) How is aniline obtained from benzene? (b) Why are the secondary amines more basic than primary amines? Explain. (c) Write the complete chemical reactions for the conversion of aniline to sulph anilic acid. (d) Mention two important uses of sulphanilic acid. (e) Write a chemical reaction of aniline which may distinguish it from ethylamin e. 5 Q. 34. Explain the following observations: 5 (i) Most of the known noble gas compounds are those of xenon. (ii) CIF exists but FCI does not. 3 3 (iii) Among the hydrides of elements of Group 16, water shows unusual physical p roperties. (iv) Unlike phosphorus, nitrogen shows little tendency for catenation. (v) Sulphur in vapour state exhibits paramagnetic behaviour. CHEMISTRY2003 (Set IOutside Delhi) < br/>Q. 1. Name one ion whose central atom has the of hybrid orbitals. 1sp typeQ. 2. Name a salt that can be added to AgCI so as to produce cation vacancies. 1 Q. 3. Which radioactive series starts from U-235 and terminates at P -207? 1 Q. 4. What is meant by shape selective catalysis? 1 Q. 5. Why is the bond dissociation energy of fluorine molecule less than that of chlorine molecule? 1 Q. 6. What is the effect of increasing pH on K Cr O Q. 7. Name the following complex using IUPAC norms: 1 Q. 8. Why is cellulose in our diet not nourishing? 1 Q. 9. Give one example each of (a) a vat dye, (b) a mordant dye. 1 solution? 1 2 7Q. 10. Mention the composition of a composite propellant. 1 Q. 11. Br ions form close packed structure. If the radius of Br m, calculate the radius of the cation that just fits in the tetrahedral hole. Can a cation A the crystal + having a radius of 82 pm be slipped into the Octahedral hole of 2ion is 195 pQ. 12. Carbon tetrachloride and water are immiscible whereas ethanol and water a re miscible in all proportions. Correlate this behaviour with molecular structures of these compounds. 2 Q. 13. What is meant by bond order? Calculate the bond orders of molecular Ions. 2 Q. 14. Why does the molar conductance increase on diluting the solution of a wea k electrolyte? Electrolytic conductivity of 0.30 M solution of KCI at 298 K is 3.72 x 10 ivity. 2 S cm -2 -1 . Calculate its molar conductQ. 15. (a) State the factors that influence the value of cell potential of the f ollowing cell: (b) Write Nernst equation to calculate the cell potential of the above cell. 2 Q. 16. What is known as activation energy? How is the activation energy affect ed by (i) the use of a catalyst and (ii) a rise in temperature? 2 ----------------------- Page 142----------------------4 Q. 17. The reaction der reaction with half-life 3.15 x 10 of SO Cl 2 s at 320 0 is a first or C. What percentage 0 would be decomposed on heating at 320 C for 90 minutes? 2 2Q. 18. Calculate the energy released (in joules) in the fusion reaction per atom of helium formed: 2 Given:Q. 19. What is adsorption? How does adsorption of a gas on a solid surface vary with (a) temperature and (b) pressure? Illustrate With the help of appropriate graphs. 2 Q. 20. Write IUIAC names of the following: 2 (i) (ii) CH - C = C - CH 3 - CHO 2Q. 21. Write one chemical equation each to exemplify the following reactions: 2 (i) Carbylamine reaction (ii) Hofmann bromamide reaction Q. 22. What are borones? How is diborane prepared on an industrial scale? Draw t he structure of diborane molecule. 2 Q. 23. Draw the structure of ferrocene and write the reaction involved hi the pr eparation of ferrocene. 2 Q. 24. Write equations used for the synthesis of (i) terylene, (ii) neoprene. 2 Q. 25 . What are phospholipids? Give their important uses. 2 Q. 26. Name the components of blood which are responsible for: 2 (i) Blood clotting (ii) Source of energy (iii) Maintaining pH of blood within a suitable range (iv) Defence against infection. Q. 27. What is meant by the statement that an electron has dual nature? Calcul ate the wavelength associated with a moving electron having a kinetic energy of 1.1375 x 10 -25 J. 3 [me = 9.1 x 10-31 kg: h = 6.6 x 10 -34 Js] Q. 28. An aqueous solution containing 1.248 g of barium chloride (molar mass = 2 08.34 mol -1 ) in 100 g of water boils at 0 100.0832 ;C. Calculate the degree of dissociation of barium chloride. 3 ----------------------- Page 143----------------------Q. 29. How is a change in free energy related to the spontaneity of a reaction? Calculate of the following reaction? 3Q. 30. Complete the following reactions: 3 Q. 31. How is aniline prepared on a large scale? How will you convert it into: 3 (i) Benzonitrile, (ii) Acetanilide? Write the reaction and the conditions in each case. Q. 32. Account for the following: 3 (a) Tendency to show -2 oxidation state diminishes from sulphur to polonium in G roup 16. (b) Boron forms electron deficient compounds. (c) PbCI is less stable than SnCl 4 . 4Q. 33. (a) Describe the preparation of acetic acid from acetlyene. (b) How can the following be obtained from acetic acid: (i) Acetone (ii) Acetaldehyde (c) In what way can acetic acid be distinguished from acetone? (d) Why do carboxylic acids not give the characteristic reactions of a carbonyl group? 5 Q. 34. (a) What is the basic difference between the electronic configurations of the transition and inner transition elements? (b) Discuss the general trends in the following properties of the 3d transition elements (21 - 29): (i) Atomic size (ii) Oxidation states (iii) Formation of coloured ions CHEMISTRY2003 (Set ICompartment Delhi)
Q. 1. Atomic number of sulphur is 16 and that of oxygen is 8. Calculate the tota l number of protons in a sulphite ion . 1 Q. 2. What is the possible value of angular momentum quantum number (1) for the unpaired electron in the atom of an element whose atomic number is 17? 1 Q. 3. In an alloy of gold and cadmium, gold crystallizes in cubic structure occu pying the corners only and cadmium fits into the face centre voids. What is the quantitative composition of the alloy? 1 Q. 4. What will happen when red blood cells are placed in water? 1 ----------------------- Page 144----------------------Q. 5. Which solution will allow greater conductance of electricity, I M NaCI at 293 K or 1 M NaCl at 323 K? 1 Q. 6. Give one important industrial use of phenyl isocyanide. 1 Q. 7. Why is hydrogen sulphide, with greater molar mass, a gas, while water a li quid at room temperature?1 Q. 8. Mention two uses of pyrophoric alloys. 1 Q. 9. How does the addition of alum purify water? 1 Q. 10. What is codon? 1 Q. 11. Write the de-Broglie education and establish a relation between wavelengt h of a moving subatomic particle and its kinetic energy. 2 Q. 12. An element occurs in BCC structure with cell edge of 300 pm. The density of the element is S. g cm -3 How many atoms of the element does 200 g of the element contain? 2 Q. 13. An aqueous solution of sodium chloride freezes below 273 K. Explain the l owering in freezing point of water with the help of a suitable diagram. 2 Q. 14. Calculate the volume of 80% (by mass) of H SO (density = 1.80 g/ml) req uired to prepare 1 litre of 0.2 molar H SO 2 4 2 4 (Relative atomic masses: H = 1,O = 16, S = 32) 2 Q. 15. Evaporation of water is an endothermic process but spontaneous. Explain. 2Q. 16. Explain the mechanism of chemical reaction between H esence of sunlight. Write any two important 2 2and Clin the probservations on such reactions.2 -3 - 1 - 1 Q. 17. What will be the initial rate of reaction if its rate constant is 10 s and the concentration of the reactant is 0.2 mol L ? What fraction of the reactant will be converted into the products in 200 seconds ? 2 Q. 18. Account for the following: (a) o-nitrophenol has lower boiling point than p-nitro-phenol. (b) The dipole moment of chlorobenzene is less than that of methyl chloride. Q. 19. Write the IUPAC names for the following: 2 (i) (ii) CH3 - CH2 - CH - COOH | Br Q. 20. In contrast to arenes, aliphatic hydrocarbons do not undergo nitration. E xplain. 2 Q. 21. Give chemical tests to distinguish between the following pairs of compoun ds: (a) 1-nitropropane an 2-nitripropane 2 (b) CH - CH 3 - NH 2 and (CH 2 ) NH 3 2Q. 22. How do the thermoplastic polymers differ from thermosetting polymers in t heir mode of formation? Give one example of each. 2 Q. 23. Why do lyophilic sols not require any stabilizing agent for their preserv ation? How is colloidal sulphur in water prepared? 2 Q. 24. What is genetic engineering? Mention two of its main objectives. 2 ----------------------- Page 145----------------------Q. 25. Answer the following: 2 (a) How does respiration impart colour to blood?(b) How do cells derive their need of ATP? Q. 26. Give three examples of sulpha drugs and write their main uses. 2 Q. 27. (a) Illustrate with an example what is meant by standard enthalpy of form ation of a compound. (b) State the relation between standard free energy change and equilibrium const ant of a chemical reaction. 0C for the processCalculate the value of Q.28. The emf of the cell has been found to be 0.305 V at 298 K. Calculate the value of M . 1 Q. 29. How will you obtain the following: (a) 1, 2etkaaedlol from ethanol (b) 2-metIi from 2 (c) Benzoic acid from chlorbenzene Give the complete chemical reaction and condition in each case. Q. 30. What happens when (write reactions only): 3 (a) Methoxybenzene Is subjected to nitration. (b) Ethanamide is reacted with HNO . 2 (c) Acetic acid is reacted with chlorine in the presence of red phosphorus. Q. 31. (a) A coordination compound has the formula CoCI liberate ammonia but forms a precipitate with 3 AgNO . Write the structure and IUPAC name of the complex compound. 3 . 4NH . It does not 3(b) Name a ligand. Which is bidentate and give an example of the complex formed by this ligand. 3 Q. 32. (a) State the principle of neutron activation analysis. 9 (b) A sample of U-238 (half -life 4.5 x 10 years) ore is found to contain 23.8 g of U-238 and 20.6 g of P -206. Calculate the ageof the ore. 3 Q. 33. Explain the following observations: 5 (a) Hydrogen fluoride has the highest boiling point among th hydrogen halides. (b) Although I.E. of lithium is maximum amongst Group 1 metals, it is the Strong est reducing agent in solution. (c) Sodium metal can be used for drying ether but cannot be used for drying (d) A nitrogen atom has five valence electrons but it does not form the compound NCI 5 . (e) Solubility of sulphates of Group 2 elements in water decreases down the grou p. Q. 34. (a) Explain the following: (i) The transition elements have high enthalpies of atomization. (ii) The d-block elements exhibit more number of oxidation states than do the fblock elements. (b) A green chromium compound A on fusion with alkali gives a yellow compound B which on acidification gives an orange coloured solution C. C on treatment with NH4 CI gives a coloured product D which on crystallization and subsequent heating decomposes to give back compound A identify A, B, C and D. Write equations for the reactions involved. 5 CHEMISTRY (Set IDelhi)
----------------------- Page 146----------------------Q. 1. Name a substance which on addition to AgCl causes vacation vacancy in it. 1 Q. 2. Mention a large scale use of the phenomenon called reverse osmosis. 1 Q. 3. Give an example of a pseudo first order reaction. 1 Q. 4. Write the JUPAC name of the following: (CH ) C=CHCOCH 3 2 3 Q. 5. Mention two properties of acetonitrile b of which it acts as a good solven t. 1 Q. 6. Draw a diagram showing the formation of bonding and antibonding molecular orbitals by the LCAO in homonuclear hydrogen molecule. 2Q. 7. Taking a specific example show that AS total is a criterion for spontaneit y of a change. 2 Q. 8. Write the cell reactions which occur in lead storage battery (i) when the battery is in use (ii) when the battery is on charging. 2 Q. 9. Give chemical reaction in support of each of the following statements: 2 (i) The +1 oxidation state gets stabilised progressively from Ga to TI in Group (ii) All the bonds PCl5 are not equivalent. Q. 10. Explain the following terms: 2 (a) Asymmetric molecule (b) R and S notations Q. 11. Write the names of the reagents and equations in the conversion of 2 (a) phenol to salicyl aldehyde (b) anisole to p-methoxyacetophenone Q. 12. Write the modes of free radical polymerization of an alkene. O r Differentiate between addition and condensation polymers based on mode of Polyme rization. Give one example of each type. 2 2 Q.13. What information is given by (i) Radial probability density, R and (ii) R adial probability function, in hydrogen atom? How do they vary with r for 1s orbital of hydrogen atom? Show dia grammatically. 3 Q. 14. Calculate the density of silver which crystallizes in the face-centred cu bic structure. The distance between the nearest silver atoms in this structure is 287 pm.3 (Molar mass of Ag = 107.87 g mol- 1, N 6.02 x 1023 mol-1) A Q. 15. Two elements A and B form compounds having molecular formulae AB and AB . dissolved in 2O g of benzene, 1 g of 2 4AB lower the freezing point by 2.3 K, whereas 1 g of AB lowers it by 1.3 K. Th e molar depression constant for benzene is 5.1 2 4 K kg mor- 1. Calculate the atomic masses of A and B. 3Q. 16. Calculate the standard gi propane at 298 k.s energy change for the formation ofQ. 17. Conductivity of 0.00241 M acetic acid is 7.896 x 10-5 S cm-1. Calculate i ts mlaor conductivity. If for acetic acid is 2 390.5 S cm mol - 1 , what is its disso-ciation constant? 3Q. 18. A reaction is first order in A and second order in B. (a) Write differential rate equation. (b) How is the rate affected if the concentration of B is tripled? (c) How is the rate affected when the concentrations of both A and B are doubled ? What is the significance of rate constant In the rate expression? 3 Q. 19. How are the colloids classified on the basis of the nature of interaction between dispersed phase and dispersion medium? Describe an important characteristic of each class. Which of these sole need sta bilising agents for preservation? 3 O r ----------------------- Page 147----------------------What are detergents? Give their scheme classification. Why are the detergen- ts preferred over soaps? Q. 20. Draw a figure to show splitting of degenerate d orbitals in an octahedral crystal field. How does the magnitude of decide the actual configuration old orbitals in a complex entity? 3 Q. 21. Write the nuclear reactions for the following radioactive decay: 3 (i) (ii) (iii) U undergoes an Ba undergoes K-capture. Pb undergoes - decay.Q.22. Draw the structure Of a carbonyl group and indicate clearly (i) the hybrid ized state of carbon, (ii) the a and bonds present and (iii) the electrophilic and nucleophilic centres in it. 3 Q. 23. (a) Identify A and B in the following: (b) Explain why the aromatic amines are less basic than ammonia and alipha-tic a mines. 3 Q. 24. On the basis of application, how are dyes classified? Describe essentialfeat-ures of any two of them. 3 Q. 25. (i) Assign appropriate reason for each of observations: (a) Anhydrous ALCI is used as a catalyst. 3 (b) Phosphinic acid behaves as a monoprotic acid. (c) SF is not easily hydrolysed whereas SF is readily hydrolysed. 6 4 (d) No form of elemental silicon is comparable to graphite. (ii) Draw the structure of XeOF or BrF . 5 4 3Q. 26. (i) How would you account for the following: (a) The transition elements exhibit high enthalpies of atomization. (b) The 4d and 5d series of the transition metals have more frequent met- al met al bonding in their compounds than do the 3d metals. (c) There is a greater range of oxidation states among the actinoids than that i n the lanthanoids. (ii). Write the complete chemical equation for each of the following: (a) An alkaline solution of KMnO reacts with an iodide. 4 (b) An excess of SnCI solution - added ton solution of mercury (II) chloride. 5 2 Q. 27. Name the products o tained on complete hydrolysis of DNA. Enumer ate the structural differences between DNA and RNA. In what way is a nucleotide dif-ferent from a nucleoside? Illustrate with e xamples. 5 O r Define and classify vitamins. Name the diseases caused due to lack of any three of them. CHEMISTRY (Set IOutside Delhi)
Q. 1. Define the term amorphous. 1 Q. 2. What is the sum of the mole fractions of all the components in a three com po-nent system? 1----------------------- Page 148----------------------Q. 3. What is meant by an elementary reaction? 1 Q. 4. Write the IUPAC name the following: 1Q. 5. Draw the structure of 4-methylpent-3-en-2-one. 1 Q. 6. Compare the relative stability of the following species and indicate their mag-netic (diamagnetic or paramagnetic) properties: 2 Q. 7. How does molar conductivity vary with concentration for (i) weak electroly te and for (ii) strong electrolyte? Give reasons for these variations. 2 Q. 8. Give the chemical reactions as an evidence for each of the following obser va-tions. 2 (i) Tin ( II ) is a reducing agent wheras Pb ( II ) is not. (ii) +1 gallium undergoes disproportionation reaction. Q. 9. Identify and indicate the presence of centre of chirality, if any, in the following molecules. How many stereoisomers are possible for those containing chiral centre? 2 (i) 1, 2-dichloropropane (ii) 3-bromo-pent-I-ene Q. 10. What happens when ethanol is heated with concentrated sulphuric acid at 4 53 K? Explain the mechanism of this reaction. 2 Q. 11. Write the mode of free radical addition polymerization of an alkene. Clea rly indicate the role of an initiator in it. 2 Q. 12. Write the major classes in which the carbohydrates are divided depending upon whether these undergo hydrolysis, and if so, on the number of products formed. 2 Or Explain mutarotation taking D-glucose as an example. Q. 13. What do you understand by (i) Radial probability density, R2 and (ii) Rad ial probability function, ? Draw the curves which show their variation with r for 2s orbital of hydrogen atom. 3Q. 14. Calculate the value of Avogadro constant from the following data: 3 Density of NaCl = 2.165 g cm--3 + Distance between Na and CI in NaCI = 281 pm (Molar mass of NaCI = 58.5 g mol- 1) Q. 15. The elements A and B form purely covalent compounds having molecular form ulae AB and AB . When dissolved in 20 2 4g of benzene, I g of AB lowers the freezing point by 2.3 K, whereas 1 g of AB lowers it by 1.3 K. The molar depression 2 4 constant for benzene is 5.1 K kg mol- 1. Calculate the atomic mass of A and atom ic mass of B. 3 Q. 16. Write the Nernst equation and calculate the e.m.f. of the following cell at 298 K: 3 2+ Cu (s) | Cu + (0.130 M) | | Ag (1.00 X 10 -4 M) | Ag (s)0 0 Given: E Cu2+/Cu = 0.34V and E Ag+/Ag = +0.80 V. Q. 17. Following reaction takes place in one step, 2NO (g) + O 2 (g) 2 NO (g). 2How will the rate of the above reaction change if the volume of the reaction ves sel is diminished to one-third of its original volume? Will there be any change in the order of the reaction with the reduced v olume? 3 ----------------------- Page 149----------------------Q. 18. Explain what is observed when 3 (i) an electrolyte is added to ferric hydroxide sol. (ii) an emulsion is subjected to centrifugation. (iii) direct current is passed through a colloidal sol. Or Define adsorption and write two important differences between physical adsorptio n and chemisorption. Q. 19. Draw a figure to show splitting of degenerate d orbitals in an octahedral field. How is the magnitude of affected by ( i)nature of ligand and (ii) oxidation state of metal ion? 3 Q. 20. Complete the following nuclear reactions: 3 (i) (ii) (iii) Mo(..n) Cm + U( Tc C --> ..+4 --> . n(Note Use symbol "X where element is not known) Q. 21. Describe simple chemical tests to distinguish between the following pairs of compounds: 3 (i) Propanal ad Propanone (ii) Phenol and Benzoic acid (iii) Diethyl ether and Propanol Q. 22. Give appropriate reasons for each of the following observations: 3 (i) The aromatic amines are weaker bases than aliphatic amines. (ii) Even under mild conditions aniline on bromination gives 2, 4, 6- tribromoan iline instantaneously. (iii) The diazonium ion acts as an electrophile. Q. 23. Enumerate the structural differences between DNA and RNA. Write down the structure of sugar present in DNA. 3 Q. 24. Describe the following with example in each case: 3 (i) Antioxidants (ii) Biodegradable detergents (iii) Hybrid propellants Q. 25. (a) What is meant by an entropy driven reaction? How can a reaction with positive enthalpy and entropy changes be made entropy driven? (b) Calculate the standard Gi pane, C H (g) at 298 K. 3 8 0 H for propane is -103.85 kJ mol . -1 s energy change for the formation of pro3C +4H (g) --> C H (g) (graphite) 2 3 8 0 -1 -1 0 2-1 -1 Given: S m C H (g) = 270.2 J K , 3 8 0mol, S m H (g) = 130.68 J Kmol-1 S m C = 5.74 J K- 1 mol .Q. 26. (i) Give reasons for the following observations: (a) The tendency for catenation decreases down the group in Group 14. (b) The decreasing stability of +3 oxidation state with increasing atomic number in Group 13. (c) SF is not easily hydrolysed through thermodynamically it should be. 6 ----------------------- Page 150----------------------(ii) Draw the structure of the following species: (a) (Si O )62 7 (b) CIO--4 Or (i) Assign reasons for the following observations: (a) PbO is a stronger oxidising agent than SnO . 2 (b) The bond energy of F is less than that of Cl . 2 (c) Sulphur in vapour state exhibits paramagnetism. (ii) Draw the structures of the following species: (a) (SiO2- ) 3 n (b) BrO--4 Q. 27. (a) Describe the variability of oxidation states in the first row of the transition elements (Sc - Cu) and indicate the general trend: (b) Write chemical reactions Involved In the following: (a) When matte is charged into silica lined converter in the metallurgy of coppe r. (ii) When a solution of chromate is acidified. (iii) A developed photographic film is subjected of fixing. 5 CHEMISTRY 2005 (Set-I Delhi) 2 2
Q. 1. What is the maximum possible coordination number of an atom in an hcp crys tal structure of an element? 1 Q. 2. State the formula relating pressure of a gas with its mole fraction in a l iquid solution in contact with it. 1 Q. 3. Express the relation between the half-life period of a reactant and its in itial concentration if the reaction involved is of second order. 1 Q. 4. How are formalin and trioxane related to methanal? 1 Q. 5. Why are primary amines higher boiling than tertiary amines. 1 -6 Q. 6. Show that the Helsenberg Uncertainty Principle is of negligible significan ce For an object of 10 kg mass. Or On the basis of Heisenberg Uncertainty Principle show that the electron (mass=9 x 10 -31 kg) cannot exist within an atomic -15 nucleus of radius 10 m. G values at 1