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MODEL PAPER CHAPTER # 6 (REMAINING + EXERCISE)CHEMISTRY OBJECTIVE TYPE Paper : 1 ROLL No.(in figures) ---------------------

TIME = 20 MINUTES MARKS : 17 (in words) ---------------------Serial No. of

A/Book:-----------------

Signature;(Candidate)

Signature(Dy.

Supdt.)NOTE: Write all answers on this very paper. According to the given instructions. Cutting,overwriting, useof lead pencil / ink remover or fluid is not allowed.

Q.No.1 Each question has four possible answers. Choose the correct the answer

andencircle it. (17)

(1). Paramagnetic behaviour of O2 could only be explained by the ------- theory. (2002,Gujranwala)(a). VSEPR (b). Molecular orbital. (c). Valence bond. (d). Lewis.

(2). Bond length of element from top to bottom in a group of the Periodic Table.(Sargodha,2005)

(a). Increases. (b). Decreases. (c). Remains same. (d). First decreases then increases.

(3). Which of the following molecules have unpaired electrons in anti bonding molecular orbitals:(a). N2 (b). B2 (c). F2 (d). O2 (NP, Gujranwala,2005)

(4). Which of these molecules has zero dipole moment. (NS,2005, Faisalabad, 2009 Multan)(a). BF3 (b). H2O (c). CHCl3 (d). NH3

(5). Which of the following species has unpaired electrons in antibonding molecular orbitals?(a). O2

2+ (b). N22 (c). B2 (d). F2 (2006, Rawalpindi, Lahore

2008)

(6). The bond order in N2 molecule is: (2006,Dera GaziKhan)

(a). 0 (b). 3 (c). 2 (d). 1

(7). Which of the HX has highest percentage of ionic character: (Lahore, 2006, D.G Khan 2009)(a). HBr (b). HCl (c). HI (d). HF.

(8). The types of bonds in nitrogen molecule are: (2005, Dera Gazi Khan)

(a). One and one . (b). One and two . (c). Two and one . (d). Three bonds.

(9). An ionic compound A+B- is most likely to be formed when(a). The ionization energy of A is high and electron affinity of B is low.(b). The ionization energy of A is low and electron affinity of B is high.(c). Both the ionization energy of A and electron affinity of B are high.(d). Both the ionization energy of A and electron affinity of B are low.

(10). Which of the following statement is not correct regarding bonding molecular orbitals?(Multan,2008)(a). Bonding molecular orbitals possess less energy than atomic orbitals from which they are formed.(b). Bonding molecular orbitals have low electron density between the two nuclei.(c). Every electron in the bonding molecular orbitals contributes to the attraction between atoms.(d). Bonding molecular orbitals are formed when the electron waves undergo constructive interference,

(11). Which of the following hydrogen halides has the highest dipole moment:(a). HCl (b). HBr (c). HF (d). HI

(12). Which of the following has nonzero dipole moment?(a). SF6 (b). CHCl3 (c). PCl5 (d). BF3

(13). The structure of a molecule can be decided on the basis of: (2009s,GRW)(a). Symmetry (b). Dipole moment (c). Polar nature (d). Size of atoms.

(14), Which of the following species has no unpaired electrons in antibonding molecular orbitals:(a). H2 (b). O2 (c). O2

1+ (d). N22

(15). Carbon dioxide and methane have dipole moment value: (GRW,2008)(a). Zero and 1.85D (b). 1.70D and 1.80D (c). Both have zero (d). None of these.

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(16). What is true about the bond lengths of the bond with higher bond energy values:(a). They have longer bond lengths. (b). They have shorter bond lengths.(c). They have intermediate bond lengths. (d). All a, b, c.

(17). CH3 O CH3 and CH3 CH2 OH are:(a). Isotopes (b). Isobars (c). Isomers (d). Isotones.

MODEL PAPER SUBJECTIVE TYPE CHAPTER # 6 (REMAINING +EXERCISE)

TIME = 40minutes MARKS : 18

NOTE: Attempt any FIVE questions from section I and any ONE question from section II.

SECTION # IQ.No.2 Attempt any FIVE questions. (5x2) =10

(1). The dipole moment of CO2 is zero and that of water is 1.85D. Why? (2004, Lahore)(2). Dipole moment of BF3 is zero. Explain it. (2004, Rawalpindi)(3). What is a bond? (2004, Bhawalpur)

(4). Why sigma bond is stronger than pi bond? (2005, Lahore)(5). Oxygen molecule is paramagnetic in nature. Explain.

(Sargodha,2005)(6). Explain the term bond order. (NS,Gujranwala,2005)(7). Distinguish between paramagnetism and diamagnetism.

(2006,Rawalpindi)(8). bonds are more diffused than bonds. (Lahore, 2006)(9). Differentiate between boding molecular orbital and antibonding molecular orbital. (2006,Multan)(10). Discuss formation of sigma molecular orbitals from s orbitals.

(11). Bond distance is the compromise distance between two atoms.(12). The distinction between a coordinate covalent bond and a covalent bond vanishes after bondformation in NH4

+, H3O+ and CH3NH3

+.(13). The bond angle of H2O and NH3 are not 109.5

0 like that of CH4. Although, O- and N-atoms aresp3 hybridized.(14). The abnormality of bond length and bond strength in HI is less prominent than that of HCl.(15). Solid sodium chloride does not conduct electricity, but when electric current is passed throughmolten sodium chloride or its aqueous solution, electrolysis takes place.

SECTION # IINOTE: Attempt any ONE question. (8)

Q. No.3 (a) Explain the formation of N2 molecules on the basis of M.O.T. (5) (2002,Gujranwala) (b) Discuss main point of Molecular Orbital Theory of covalent bonding. (3) (O.C, 2003,Sargodha)

Q. No.4 (a) Define dipole moment. Give its units and its applications. (1,1,3) (O.C, 2003,Sargodha)

(b) Explain the factors on which strength of bond depends. (3) (N.C, 2003,Bhawalpur)

Q. No.5 (a) Explain the formation of O2 molecule with the help of molecular orbital theory.(5) (O.C, 2003, Bhawalpur)

(b) Justify the helium molecule does not exist. (3)

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