Electrochemistry

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1Which of the following substances Na, Hg, S, Pt and graphite can be used as electrodes in electrolytic cells having aqueous solution?( )Na, Pt and graphite

( )Na and Hg

( )Pt and graphite

( )Na and S

Single Answer

2When quantity of electricity passed is one faraday then the mass deposited at the electrode is equal to( )One gm.atomic weight

( )One gm.Equavalent weight

( )Electrochemical equivalent

( )None of the above

Single Answer

3If a salt bridge is removed between the two half cells, the voltage ( )Drops to zero

( )Does not change

( )Increases gradually

( )Increases rapidly

Single Answer

4The reference calomel electrode is made from which of the following?( )ZnCl2

( )CuSO4

( )Hg2Cl2

( )HgCl2

Single Answer

5When electricity is passed through molten Al2O3+Na3AlF6 and 13.5gms of Al are deposited, the number of faradaymust be( )0.5

( )1.0

( )1.5

( )2.0

Single Answer

6An electrode( )Forms complex ions in solution

( )Gives ions only when electricity is passed

( )Possesses ions even in solid state

( )Gives ions only when dissolved in water

Single Answer

7A cell constant is generally found by measuring the conductivity of aqueous solution of( )BaCl2

( )KCl

( )NaCl

( )MgCl2

Single Answer

8A solution of sodium sulphate was electrolysed using some inert electrodes. The products at the electrodes are( )O2,H2

( )O2,Na

( )O2,SO2

( )O2,S2O8^2-

Single Answer

9A current of 9.65A flowing for 10 minutes deposits 3.0 g of the metal which is monovalent. The atomic mass of the metal is( )10

( )50

( )30

( )96.5

Single Answer

10A certain current liberates 0.5 g of hydrogen in 2 h. How many grams of copper can be liberated by the same current flowing for the same time in a copper sulphate solution?( )12.7g

( )15.9g

( )31.8g

( )63.5g

Single Answer

11Out of Cu, Ag, Fe and Zn the metal which can displace all others from their salt solutions is( )Ag

( )Cu

( )Zn

( )Fe

Single Answer

12The conductivity of strong electrolyte( )Increases on dilution slightly

( )Does not change on dilution

( )Decreases on dilution

( )Depends on density of electrolyte itself

Single Answer

13The amount of electricity that can deposit 108 g of silver from silver nitrate solution is( )1 ampere

( )1 coulumb

( )1 faraday

( )2 amperes

Single Answer

14In a galvanic cell( )Chemical energy is converted into electricity

( )Chemical energy is converted into heat

( )Electrical energy in converted into heat

( )Electrical energy is converted into chemical energy

Single Answer

15When electricity is passed through molten electrolyte consisting of alumina and cryolite, 13.5 g of Al are deposited. The number of faradays of electricity passed must be( )2.0

( )1.5

( )1.0

( )0.5

Single Answer

16Which of the following is a strong electrolyte?( )Ca(NO3)2

( )HCN

( )CH3COOH

( )NH4OH

Single Answer

17Pure water does not conduct electricity because it( )Has low boiling point

( )Is almost unionized

( )Is neutral

( )Is readily decomposed

Single Answer

1896500 C of electricity liberates from CuSO4 solution( )63.5 g of Cu

( )31.75 g of Cu

( )96500 g of Cu

( )100 g of Cu

Single Answer

19Which of the following is the use of electrolysis?( )Electrorefining

( )Electroplating

( )Both a and b

( )None of the above

Single Answer

20In a solution of CuSO4 how much time will be required to precipitate 2g Cu by 0.5 ampere current?( )12157.48 sec

( )102 sec

( )510 sec

( )642 sec

Single Answer

212.5 faraday of electricity is passed through solution of CuSO4. The number of gram equivalents of copper deposited on the cathode would be( )1

( )2

( )2.5

( )1.25

Single Answer

22Reaction takes place at anode is( )Ionization

( )Reduction

( )Oxidation

( )Hydrolysis

Single Answer

2396500 C electricity is passed through CuSO4. The amount of copper precipitated is( )0.25 mole

( )0.5 mole

( )1.0 mole

( )2.0 mole

Single Answer

24The art of electroplating was given by( )Faraday

( )Edison

( )Thomas Gradam

( )Brugan

Single Answer

25The number of coulumbs required for the deposition of 107.870 g of silver is( )96500

( )48250

( )193000

( )10000

Single Answer

26What will be the weight of deposited silver on passing 965 coulumbs of electricity in solution of AgNO3?( )1.08 g

( )2.16 g

( )0.54 g

( )0.27 g

Single Answer

27Pick out the wrong statement. In electrochemical cell( )Electrons are released at anode

( )Cathode is regarded as negative electrode

( )Chemical energy is converted into electrical energy

( )Salt bridge maintains the electrical neutrality of the solution

Single Answer

28Prevention of corrosion of iron by Zn coating is called( )Galvanization

( )Cathodic protection

( )Electrolysis

( )Photoelectrolysis

Single Answer

29The specific conductance of a 0.1 N KCl solution at 23 degree calsius is 0.012 /ohm.cm. The resistance of cell containing the solution at the same temperature was found to be 55 ohm. The cell constant will be( )0.14/cm

( )0.66/cm

( )0.918/cm

( )1.12/cm

Single Answer

30The substance having highest conductivity at room temperature among the following is( )0.1 N HCl

( )0.1 N NaCl

( )Graphite

( )Glass

Single Answer

31Best way to prevent rusting of iron is by( )Making iron cathode

( )Putting it in saline water

( )Both of these

( )None of these

Single Answer

32The specific conductance of 0.1 M NaCl solution is 1.06x10^-2 /ohm.mol. Its molar conductance in ohm^-1.cm2.mol^-1 is( )1.06x10^2

( )1.06x10^3

( )1.06x10^4

( )53

Single Answer

33Calculate the amount of charge flowing in 2 minute in a wire of resistance 10 ohm when a potential difference of 20 V is applied( )120 C

( )240 C

( )20 C

( )4 C

Single Answer

34The equivalent conductivity of 0.1 M week acid is 100 times less than that at infinite dilution. The degree of dissolution is( )100

( )10

( )0.01

( )0.001

Single Answer

35The standard EMF of Daniel cell is 1.10 volt. The maximum electrical work obtained from Daniel cell is( )212.3 kJ

( )175.4 kJ

( )106.15 kJ

( )53.07 kJ

Single Answer

36Conductivity (unit: siemen S) is directly proportional to the area of the vessel and the concentration of the solutin in it and is inversly proportional to the length of vessel, then the unit of constant of proportionality is( )Sm/mol

( )Sm2/mol

( )S-2 m2 mol

( )S2m2/mol-2

Single Answer

37A smuggler could not carry gold by chemically depositing iron on the gold surface since( )Gold is denser

( )Iron rusts

( )Gold has higher reduction potential than iron

( )Gold has lower reduction potential than iron

Single Answer

38In electrolysis of NaCl when Pt electrode is taken then H2 is liberated at cathode while with Hg cathode it forms sodium amalgam( )Hg is more inert than Pt

( )More voltage is required to reduce H+ at Hg than at Pt

( )Na is dissolved in Hg while it does not dissolve in Pt

( )Conc. of H+ ions is larger when Pt electrode is taken

Single Answer

39Corrosion is basically( )Altered reaction in presence of H2O

( )Electrochemical phenomenon

( )Interaction

( )Union between two light metals and a heavy metal

Single Answer

40The unit of conductiviyt is( )Ohm/cm

( )Ohm.cm2

( )Ohm-1.cm

( )Ohm-1.cm-1

Single Answer

41When during electrolysis of a solution of AgNO3, 9650 coulombs of charge pass through the electroplating bath, the mass of silver deposited on the cathode will be( )1.08 g

( )10.8 g

( )21.6 g

( )108 g

Single Answer

42Standard reduction electrode potential of three metals A, B and C are respectilvely +0.05V, -3.0 and -1.2 V. The reducing power of( )B>C>A

( )A>B>C

( )C>B>A

( )A>C>B

Single Answer

43Same amount of electric current is passed through solutions of AgNO3 and HCl. If 1.08 g of silver is obtained in the first case, the amount of hydrogen liberated as S.T.P in the second case is( )112 cm3

( )22400 cm3

( )224 cm3

( )1.008 g

Single Answer

44Time required to deposit one millimole of aluminium metal by the passage of 9.65 amperes through molten electrolyte containing aluminium ion is( )30 s

( )10 s

( )30,000 s

( )10,000 s

Single Answer

45Which of the following (IM) conducts more electricity?( )Sulphuric acid

( )Boric acid

( )Nitric acid

( )Phosphorus acid

Single Answer

46If the standard electrode potential of CU2+/Cu electrode is 0.34 V, what is the electrode potential of 0.01 M concentration of Cu2+? (T=298 K)( )0.399 V

( )0.281 V

( )0.222 V

( )0.176 V

Single Answer

47An electric current is passed through silver voltameter connected to a water voltmeter. The cathode of the silver voltameter is 0.108 g more at the end of the electrolysis. The volume of oxygen evolved at S.T.P is( )56 cm3

( )550 cm3

( )5.6 cm3

( )11.2 cm3

Single Answer

48An electric current is passed through silver nitrate solution using silver electrodes. 10.79 g of silver was found to be deposited on the cathode if the same amount of electricity is passed through the copper sulphate solution using copper electrodes, the weeight of the copper deposited on the cathode is( )6.4 g

( )2.3 g

( )12.8 g

( )3.2 g

Single Answer

49The standard e.m.f of a galvanic cell involving cell reaction with n=2 is found to be 0.295 V at 25 degree calcius. The equilibrium constant of the reaction would be( )1.0x10^10

( )2.0x10^11

( )4.0x10^12

( )1.0x10^2

Single Answer

50Fro spontanity of a cell, which is correct?( ) dG=0, dE=0

( ) dG=-ve, dE=0

( ) dG=+ve, dE=0

( ) dG=-ve

Single Answer

51Specific conductivity of a solution( )Increases with dilution

( )Decreases with dilution

( )Remains unchanged with dilution

( )Depends on mass of electrolyte

Single Answer

52In a Galvanic cell, the electrons flow from( )Anode to cathode through the solution

( )Cathode to anode through the solution

( )Anode to cathode through the external circuit

( )Cathode to anode through the external circuit

Single Answer

53In a hydrogen-oxygen fuel cell, combustion of hydrogen occurs to( )Generate heat

( )Remove absorbed oxygen from electrode surfaces

( )Produce high purity water

( )Create potential difference between two electrodes

Single Answer

54The limiting molar conductivities ^ for NaCl, KBr and KCl are 126, 52 and 150 Scm2 respectively. The ^ for NaBr is( )128 Scm2/mol

( )302 Scm2/mol

( )278 Scm2/mol

( )176 Scm2/mol

Single Answer

55When a non-spontaneous reaction takes place at the expense of electrical energy the process is called( )Electrolysis

( )Ionization

( )Neutralization

( )Electrical conduction

Single Answer

56Using inert electrodes like Pt or graphite the electrolysis of aqueous sodium chloride produces at cathode( )Cl2 gas

( )H2 gas

( )O2 gas

( )HCl gas

Single Answer

57In the presence of copper electrodes the electrolysis of aqueous CuSO4 produces at cathode( )H2 gas

( )O2 gas

( )SO2 gas

( )Cu metal

Single Answer

58The cathodic reaction in the electrolysis of dil.H2SO4 with Pt electrodes( )Reduction

( )Oxidation

( )Both oxidation and reduction

( )Neither oxidation nor reduction

Single Answer

59Which of the following statement about galvanic cell is true( )Anode is negatively charged

( )Reduction occurs at anode

( )Cathode is positively charged

( )Reduction occurs at cathode

Single Answer

60The electrode through which the electons enter the electrolytic solution is ( )Anode

( )Cathode

( )May be anode or cathode

( )None of these

Single Answer

61If the salt bridge is not used between two half cells, then the voltage( )Decrease rapidly

( )Decrease slwly

( )Does not change

( )Drops to zero

Single Answer

62When fused PbBr2 is electrolyzed( )Bromine appears at the cathode

( )Lead appears at the cathode

( )Lead appears at the anode

( )None of these

Single Answer

63When electric current is used t carry out non-spontaneous redox reaction, the process is called( )Hydrolysis

( )Electrolysis

( )Decomposition

( )Neutralization

Single Answer

64By using graphite electrode the electrolysis of aqueous solution of NaCl produces at anode( )H2 gas

( )Cl2 gas

( )NaOH

( )Na metal

Single Answer

65The electrolysis of CuSO4 aqueous solution using copper as cathode as well as anode the substance which is deposited at cathode is( )H2SO4

( )Oxygen

( )Copper

( )Hydrogen

Single Answer

66An electrochemical cell in which a spontaneous oxidation reduction reaction generates electrical current is called( )Electrolytic cell

( )Galvanic or voltaic cell

( )Dry cell

( )All the above

Single Answer

67In the electolysis of aqueous solution of sodium nitrate, the ions which are reduced at the cathode are( )H3O+

( )Na+

( )OH-

( )NO^3-

Single Answer

68In the elctrolysis of aqueous solution of NaCl, the reaction which takes place at cathode is( )Reduction of Na+ ions

( )Reduction of H+ ions

( )Reduction of H2O molecules

( )Discharge of Cl- ions

Single Answer

69Purification of an impure copper is made by electrolytic cell, in which impure copper is anode and pure copper is cathode, and the electrolyte is( )H2SO4

( )CuSO4

( )ZnSO4

( )Na2SO4

Single Answer

70The cell which generates electicity as a result of spontaneous oxidation-reduction reaction is called( )Electrolytic cell

( )Nelson's cell

( )Galvanic cell

( )Down's cell

Single Answer

71The function of salt bridge in the galvanic or voltaic cell is to( )Carry out oxidation at anode

( )Carry out reduction at cathode

( )Carry out electrolysis

( )Prevent the net charge accumulation in either of the half cells

Single Answer

72In voltaic cell the elctrode reactions are reversed when( )Salt bridge is removed

( )Voltaic cell is connected to SHE

( )External circuit is replaced by a source of electricity

( )H2SO4 is added to cell

Single Answer

73When a metal is dipped in 1 molar of its solution at 298 K, then potential set up is called( )Standard selctrode potential

( )Electric charge

( )Ionization potential

( )Electroplating

Single Answer

74A standard hydrogen electrode is used as standard electrode of which electrode potential is arbitrarily taken as( )+1

( )-1

( )0.1

( )Zero

Single Answer

75The reduction potential of copper electrode is +0.34 V and that of Zn electrode is -0.76 V. When these two are coupled the emf of the cell is( )-0.42 V

( )+0.42 V

( )-1.10 V

( )+1.10 V

Single Answer

76Coupling of Pb with its Pb++/Pb=-0.13 V and Ag with Ag+/Ag=+0.80 V, the cell reaction is( )Ag+2Pb+----->Ag++ +2Pb

( )2Ag+ +Pb----->Pb++ +2Ag

( )Ag+ +Pb----->Ag+Pb^+

( )Ag+Pb^+----->Ag+ +Pb

Single Answer

77A cell reaction is 2Al+3Cl2------->2AlCl3 the cell is represented as( )Al(1.0 M)/Al+++ Cl-(1.0 M)/Cl2

( )Cl2/Cl (1.0 M) Al+++(1.0 M/Al)

( )2Cl-(1.0 M)/Cl2 Cl2 Al/Al++(1.0 M)

( )Al+++(1.0 M)Al Cl-(1.0 M)/Cl2

Single Answer

78Electrochemical series is a list of elements arranged into the increasing order of their( )Standard oxidation potential

( )Standard reduction potential

( )Cell voltage

( )Ionization potential

Single Answer

79The voltaic or galvanic cells which cannot be recharged are called( )Primary cells

( )Secondary cells

( )Infinite cells

( )Fuel cells

Single Answer

80The galvanic or voltaic cells which are recharged are called as( )Primary cells

( )Secondary cells

( )Dry cells

( )Infinite cells

Single Answer

81A cell having PbO2 as cathode and metallic lead as anode and electrolyte is 30% H2SO4, then this cell is called( )Car battery

( )Alkaline battery

( )Fuel cell

( )Dry cell

Single Answer

82Lead accumulators contain( )30% NaCl solution as electrolyte

( )30% HCl solution as electrolyte

( )30% H2SO4 solution as electrolyte

( )30% NaOH solution as electrolyte

Single Answer

83The difference of potential of a cell consisting of a particular electrode and standard hydrogen electrode is called( )Electrode potential

( )Standard cell potential

( )Half cell reaction

( )None of these

Single Answer

84Which statement is incorrect about Standard Hydrogen Electrode(SHE)( )Its oxidation and reduction potential is zero

( )It consists of Pt wire dipped in 1 molar HCl solution

( )The electrolyte is 1 molar NaOH solution

( )H2 gas is passed in it at 1 atmospheric pressure

Single Answer

85Which of the following takes place spontaneously( )MgCl2 + Zn-------->ZnCL2 + Mg

( )H2 + AgNO3------>2HNO3 + 2Ag

( )2AlCl3-------->2Al + 3 Cl2

( )I2 + 2KCl--------->2KI + Cl2

Single Answer

86Which one of the following is non-spontaneous( )Zn + CuSO4----->ZnSO4 + Cu

( )Pb + 2AgNO3------->Pb(NO3)2 + 2Ag

( )2FeCl3 + H2------>6HCl + 2Fe

( )Ni + CaCl2-------->NiCl2 + Ca

Single Answer

87Alkaline battery has voltage of( )4.5 V

( )3.5 V

( )2.5 V

( )1.5 V

Single Answer

88After replacing of car battery (lead accumulator) the density of H2SO4 is( )1.0 grams/cm3

( )1.15 grams/cm3

( )1.25 grams/cm3

( )2.15 grams/cm3

Single Answer

89A dry cell has porous Zn anode and MnO2 as cathode the electrolyte used is( )Ca(OH)2

( )NaOH

( )KOH

( )NH4OH

Single Answer

90In electronic watches or elctronic calculators the tiny batteries used are( )Alkaline battery

( )NICAD battery

( )Fuel cell

( )Silver oxide battery

Single Answer

91The overall cell reaction 2H2(g) + O2(g)------>2H2O(l) in which KOH is used as an electrolyte, the cell is called( )Alkaline battery

( )Dry cell

( )Fuel cell

( )Electrolytic cell

Single Answer

92Silver oxide battery has a voltage of( )2.0 V

( )1.5 V

( )2.5 V

( ).0 V

Single Answer

93Lead accumulator stops discharging current when( )Lead at anode is converted to PbO2

( )PbO2 at cathode converted to Pb

( )Both electrodes are completely covered with PbSO4

( )Both electrodes are completely covered with Pb(OH)2

Single Answer

94Which statement is incorrect for NICAD battery( )The electrolyte is alkali

( )Cd acts as anoe

( )MnO2 acts as electrolyte

( )NiO2 acts as cathode

Single Answer

95Which statement is correct for the fuel cell( )These cells operate at low temperature

( )No catalyst used for the formation of water

( )MnO2 is used as electrolyte

Single Answer

96The oxidation number of H is -1 in the compound( )H2O

( )H2BO3

( )NaOH

( )NaH

Single Answer

97In F2O the oxidation number of oxygen is( )-2

( )-1

( )+1

( )+2

Single Answer

98The oxidation number of Mn in KMnO4 is( )+2

( )+4

( )+6

( )+7

Single Answer

99The oxidation state of Cr in K2Cr2O7 is( )+3

( )+6

( )+9

( )+4

Single Answer

100In a compound an atom has negative oxidation states because( )Atom is negatively charged

( )Atom acts as cathode

( )Atom is more electronegative

( )Atom has lowest ionization energy

Single Answer

101An oxidizing agent in a chemical reaction is the substance which( )Loses electron

( )Gains electrons

( ) pH is changed

( )Ascts as catalyst

Single Answer

102In the reaction Cu + HNO3------>Cu(NO3)2 + NO + H2O the atom which is oxidized( )Cu

( )H

( )N

( )O

Single Answer

103Metals like Pb, Sn, Ni, Co and Cd react vry slowly with steam to produce H2 gas beacuse( )These have maximum reduction

( )These have minimum reduction potential values

( )Their reduction potential value are very close to SHE

( )Their ionization potential values are minimum

Single Answer

104Coinage metals like Au, Pt, Ag and Cu are the least reactive metals and don't liberate H2 gas when treated with acids because( )These have very high positive values of reduction potential

( )These have high negative values of reduction potential

( )Their ionization potentials are lowest

( )Their reduction potentials are close to SHE

Single Answer

105Metals like Fe, Mg, Al, Cr, Zn have more negative reduction potentials that is why( )These don't react with steam

( )These react very slowly with steam to lierate H2 gas

( )These react rapidly with steam to produce the metallic oxides and liberate H2 gas

( )These react with cold water violently

Single Answer

106Which statement is incorrect for balancing of redox reactions by ion-electron method( )The reaction is splitted into two reactions

( )H2O and H+ ions are added for acidic or neutral reaction to balance O and H atoms

( )To balance H, HCl is added

( )To balance O and H in the alkaline reaction OH- added

Single Answer

107Li has lowest reduction potential while the element with highest reduction potential is( )H

( )F

( )O

( )N

Single Answer

108In passage of electricity through aqueous solution of AgNO3 silver dissolves at anode to form Ag+, the electrodes are( )Silver metal

( )Pt metal

( )Graphite

( )Copper metal

Single Answer

109When aqueous solution of NaOH is electrolyzed using graphite electrodes, the product obtained at anode is( )O2 gas

( )H2 gas

( )Na metal

( )Na2O

Single Answer

110An electrolytic cell consisiting of chromic acid electrolyte using Al metal as anode , the product obtained at anode is( )Cr metal

( )H2 gas

( )Cr2O3

( )Anodized Al

Single Answer

111In the electrolysis of fused bauxite (Al2O3.2H2O) with fused Cryolite (Na3 AlF6) using carbon rods as anode, the product obtained at cathode is( )Na metal

( )F2 gas

( )Al metal

( )O2 gas

Single Answer

112F2, Cl2, Br2 and I2 lie below SHE in the electro chemical series that is why these( )Undergo reduction

( )Undergo oxidation

( )Liberate H2 gas with steam

( )None of these

Single Answer

113In KO2 the oxidation state of oxygen is( )-2

( )-1

( )+1/2

( )-1/2

Single Answer

114Fe displace Cu from CuSO4 solution because( )Fe is ferromagnetic

( )Fe is below Cu in electrochemical series

( )Fe is above Cu in electro chemical series

( )Fe exists in divalent state

Single Answer

115Zn does not displace Mg from MgSO4 solution because( )Zn is more electropositive than Mg

( )Zn is below Mg in electrochemical series

( )Zn is above Mg in electrochemical series

( )Zn is trivalent Mg is divalent

Single Answer

116Standard reduction of Zn=-0.76 V and that of Ni is -0.25 V. On coupling them by a salt bridge which of these will act as anode( )Salt bridge

( )Zn

( )Ni

( )None of these

Single Answer

117Which statement is correct for balancing of redox reactions by oxidation number method( )Equate the increase and decrease in oxidation state of the atoms

( )Electrons are added or subtracted to balance oxidation number

( )Split the reaction into two halves

( )Add H2O and H+ to balance O and H atoms

Single Answer

118In the raction Cr(OH)3 + NaOH + H2O2-------->Na2CrO4 + H2O balancing of O atoms is done by( )Adding H2O and H+ ions

( )Adding OH- ions

( )Adding O2 molecules

( )Adding O atoms

Single Answer

119A standard hydrogen elecrtode (S.H.E) consists of a platinized platinum eletrode dipped in 1 molar solution of H+ ions and hydrogen gas is passed at a pressure of( )One Pascal

( )One kilo Pascal

( )One atm

( )Ten atm

Single Answer

120The standard electrode reduction potential of Li in Li+ + e-------->Li is -3.045. This shows Li is( )A strong reducing agent

( )A strong oxidizing agent

( )Better oxidizing agent then hydrogen

( )Less reducing agent then hydrogen

Single Answer

121The reduction potential of I2=+0.535 V, Br2=+1.08 V, Fe=+0.77 V shows that( )Iodine can oxidise iron

( )Bromine can oxidise iron

( )Iodine can oxidise bromine

( )Iron can oxidise bromine

Single Answer

122The reduction potentials are Zn^2+/Zn=-0.76 V; Cu^2+/Cu=+0.34 V, what is the E cell for the spontaneous reaction( )-1.10 V

( )+1.10 V

( )-0.42 V

( )+0.42 V

Single Answer

123In the reaction 2Fe+3Cl2------>2FeCl3( )Fe is reduced

( )Fe is oxidized

( )Cl2 is oxidized

( )None of these

Single Answer

124In electrolysis of molten sodium chloride in Down's cell the reaction which occurs at cathode is( )2NaCl(l)------->2Na+(l)+2Cl-(l)

( )2Na+(l)+2e----->2Na(l)

( )2Cl-(l)----->Cl2(g)

( )4H2O(l)------->4H+(aq)+4OH-(aq)

Single Answer

125In the extraction of aluminum, bauxite is purified by dissolving alumina in concentrated aqueous solution of sodium hydroxide which converts it into( )Sodium oxide

( )Sodium aluminum hydroxide

( )Aluminum hydroxide

( )Sodium aluminate

Single Answer

126Aluminum hydroxide precipitate in the extraction f aluminum is heated. The reaction is( )4Al(OH)3(s)-----heat------>4Al(l)+6H2O(g)+3O2(g)

( )2Al(OH)3(s)------heat------>Al2O3(s)+3H2O(g)

( )4Al(OH)3(s)------heat----->4Al(s)+6H2O(g)+3O2(g)

( )2Al(OH)3(s)-------heat---->2Al(s)+3H2(g)+3O2(g)

Single Answer

127In the electrorefining of blistered copper; electrodes are suspended in a solution containing copper sulphate, sulphuric acid and hydrochloric acid. In this process( )Blistered copper acts as cathode and pure copper as anode

( )Anode and cathodes are made up of pure copper

( )Anode and cathode are made up of blistered copper

( )Blistered copper acts as anode and pure copper as cathode

Single Answer

128During the purification of blistered copper by electrolysis less reactive metals like platinum, gold and silver deposit as anode mud or anode sludge. While( )Cathodes are gradually consumed and anode grows in size

( )Anodes are gradually consumed and cathodes grow in size

( )Both anodes and cathodes are gradually consumed

( )Non of the electrode is consumed during the process

Single Answer

129Regarding electrolytic and voltaic cells the true statement is( )In voltaic cell a non-spontaneous reaction generates electric current

( )In voltaic cell a spontaneous reaction generates electric current

( )In electrolytic cell a spontaneous reaction generates electric current

( )In eletrolytic cell a non-spontaneous raction generates electric current

Single Answer

130All of the following statements about Daniell cell are incorrct except( )Copper losses electrons

( )Zinc ions gain electrons

( )Copper is oxideized and zinc is reduced

( )Zinc rod is suspended in zinc sulphate solution

Single Answer

131Having Daniell cell in miind the incorrect statement is( )Copper is reduced

( )Zinc is oxidized

( )Copper is in direct contact with copper sulphate solution

( )Daniel cell is rechargeable

Single Answer

132Mr.Chemist was studying Daniel cell for one hour. At the end he raised his head and exclaimed haaa!!!!( )Both zinc and copper are good conductors

( )None of them is able to drag electrons from the other

( )Zinc acts as anode and copper as cathode

( )Copper acts as anode and zinc as cathode

Single Answer

133Standard hydrogen electrode is connected with an unknown half cell. If standard hydrogen electrode acts as cathode then half reaction for standard hydrogen electrode be( )H2------->2H+ +2e

( )2H+ +2e----->H2

( )2H+ +2e------->2H

( )2H----->H2

Single Answer

134Oxidation state of manganese in KMnO4 is( )+5

( )+7

( )+3

( )+2

Single Answer

135Consider the following redox reaction: 3Cu+2HNO3+HNO3------>3Cu(NO3)2 + 2NO + H2O. In this reaction( )Copper losses 2 electrons and nitrogen gains 2 electrons

( )Copper gains 3 electrons and nitrogen gains 3 electrons

( )Copper losses 4 electron and nitrogen gains 4 electrons

( )Copper losses 6 electrons and nitrogen gains 6 electrons

Single Answer

136Consider the half reaction Cr2O7^2- +6e- ------->2Cr^3+. To balance charge in acidic medium( )14 H+ should be added to the right side

( )14 H+ should be added to the left side

( )12 H+ should be added to the right side

( )12 H+ should be added to the left side

Single Answer

137If cell potential is positive then reaction will be( )Non-spontaneous in the forward direction

( )Spontaneous in the forward direction

( )Spontaneous in the reverse direction

( )Non-spontaneous in the forward direction but spontaneous in the reverse direction

Single Answer

138Dry cell, alkaline cell and mercury cell are the types of( )Primary cells

( )Secondary cells

( )Fuel cells

( )Rchargeable cells

Single Answer

139In lead-acid storage batteries Pb and PbO2 acts as( )Electrolyte

( )Charge storage plates

( )Anode and cathode respectively

( )Cathode and anode respectively

Single Answer

140Anodic reaction for lead-acid storage batteries is( )Pb(s) + SO4^2-(aq)-------->PbSO4(s) + 2e

( )PbSO4(s) + 2e---------->Pb(s) + SO4^2-(aq)

( )Pb(s)-------->Pb^2+9aq) + 2e

( )Pb^2+(aq) +2e----->Pb(s)

Single Answer

141Reagarding batteries all of the following tatements are incorrect except that( )Mercury cell is primary cell while nickel cadmium cell is secondary cell

( )Mercury cell is secondary cell while nickel-cadmium cell is primary cell

( )Both mercury and nickel-cadmium cells are primary cells

( )Both mercury and nickel cadmium cells are secondary cells

Single Answer

142In a fuel cell reactants are continuously added and the products are continuously removed. Cell reaction for hydrogen-oxygen fuel cell is( )1/2 O2(g) + H2O(l) +2e-------->2OH-(aq)

( )H2(g) + 2OH-(aq)------->2H2O(l) + 2e

( )H2(g) + 1/2 O2(g)--------->H2O(l)

( )H+ (aq) + OH-(aq)------->H2O(l)

Single Answer

143Reduction potential of copper is greater than that of magnesium which means that the following reaction is spontaneous( )Cu^2+(aq) + 2e------->Cu(s)

( )Mg(s)------->mg^2+(aq) + 2e

( )Cu(s) + Mg^2(aq)--------->Cu^2+(aq) + Mg(s)

( )Cu^2+ + Mg(s)-------->Cu(s) + Mg^2+(aq)

Single Answer

144Consider the cell reaction Pb + 2Ag^+--------->Pb^2+ +2Ag. If a cell is made based on this equation then( )Lead will act as anode and silver as cathode

( )Lead will act as cathode and silver as anode

( )Silver will act as cathode because it has greater reduction potential

( )Lead will act as anode because it has lesser reduction potential

Single Answer

145Choose the correct statement( )Oxidation state of N in NO and N2O5 is +5 and +2 respectively

( )Oxidation state of N in NO and N2O5 is +1 and +5 respectively

( )Oxidation state of N in NO and N2O5 is +2 and +5 respectively

( )Oxidation state of N in NO and N2O5 is +2 and +4 respectively

Single Answer

146Which of the following statement is correct for the life period of a galvanic cell( )It increases with increase in concentration of cathodic solution

( )It increases with increase in concentration of anodic solution

( )It increases with increase in the size of the cathode

( )It increases with decrease in the size of the anode

Single Answer

147A spontaneous reaction is for a galvanic cell as non spontaneous reaction is for( )Nelson's cell

( )Down's cell

( )Electrolytic cell

( )Daniel cell

Single Answer