CBSE Class 11 Chemistry Chemical Bonding And Molecular Structure Worksheet Set A

Question. B.P. of H₂ O(100ºC) and H₂ S(−42ºC) explained by:
a. Vander Waal's forces
b. Covalent bond
c. Hydrogen bond
d. Ionic bond
Answer : C

Question. In which of the following compounds intramole-cular hydrogen bond is present?
a. Ethyl alcohol
b. Water
c. Salicylaldehyde
d. Hydrogen sulphide
Answer : C

Question. Hydrogen bonding is formed in compounds containing hydrogen and: 
a. Highly electronegative atoms
b. Highly electropositive atoms
c. Metal atoms with d-orbitals occupied
d. Metalloids
Answer : A

Question. Which contains strongest H-bond?
a. O−H.....S
b. S−H.....O
c. F −H.....F
d. S−H.....O
Answer : C

Question. Which of the following hydrides are ionic?
a. CaH₂
b. BaH₂
c. SrH₂
d. BeH₂
Answer : ABC

Question. Which of the following conduct electricity in the fused state?
a. BeCl₂
b. MgCl₂
c. SrCl₂
d. BaCl₂
Answer : BCD

Question. CO₃²⁻ anion has which of the following characteristics:
a. Bonds of unequal length
b. 2 sp hybridization of C atom
c. Resonance stabilization
d. Same bond angles
Answer : ALL

Question. Select the compound from the following which dissolves in water?
a. CCl₄
b. CS₂
c. CHCl₃
d. C₂H₅OH
Answer : D

Question. Which molecule does not show zero dipole moment?
a. BF₃
b. NH₃
c. CCl₄
d. CH₄
Answer : B

Question. The dipole moment of HBr is 1.6 x 10⁻³⁰ cm and interatomic spacing is 1Å. The % ionic character of HBr is:
a. 7
b. 10
c. 15
d. 27
Answer : B

Question. Which one of the following molecules is expected to exhibit diamagnetic behavior?
a. C₂
b. N₂
c. O₂
d. S₂
Answer : AB

Question. Dipole moment is shown by:
a. 1, 4-dichlorobenzene
b. cis-1, 2- dichlorobenzene
c. trans-1, 2- dichlorobenzene
d. trans-1, 2-dichloro-2-pentene
Answer : BD

Question. Hydrogen bonding plays a central role in the following phenomena:
a. ice floats in water
b. higher Lewis basicity of primary amines than tertiary amines in aqueous solutions
c. formic acid is more acidic than acetic acid
d. dimeristaion of acetic acid in benzene
Answer : ABD

Question. Formula of a metallic oxide is MO. The formula of its phosphate will be:
a. M₂(PO₄)₂
b. M(PO₄)
c. M₂PO₄
d. M₃(PO₄)₂
Answer : D

Question. The electronic structure of four elements A, B, C, D are:
a. 1s²
b. 1s² , 2s² 2p²
c. 1s² , 2s² 2p⁵
d. 1s² , 2s² 2p⁶
Answer : C

Question. If HCl molecule is completely polarized, so expected value of dipole moment is 6.12D (deby), but experimental value of dipole moment is 1.03D. Calculate the percentage ionic character:
a. 17
b. 83
c. 50
d. Zero
Answer : A

Question. Which bond angle θ would result in the maximum dipole moment for the tri-atomic molecule YXY?
a. θ = 90^o
b. θ = 120^o
c. θ = 150^o
d. θ = 180^o
Answer : A

Question. Which molecules has zero dipole moment?
a. H₂O
b. CO₂
c. HF
d. HBr
Answer : B

Question. CO₂ is isostructural with:
a. HgCl₂
b. C₂H₂
c. SnCl₂
d. NO₂
Answer : AB

Question. The linear structure assumed by:
a. SnCl₂
b. CS₂
c. NO₂⁺
d. NCO⁻
Answer : BCD

Question. Which of the following have identical bond order?
a. CN⁻
b. O₂⁻
c. NO⁺
d. CN⁺
Answer : AC

Question. The molecules that will have dipole moment are:
a. 2, 2-dimethyl propane
b. trans-2pentene
c. cis-3-hexene
d. 2, 2, 3, 3-tetramethyl butane
Answer : BC

Assertion and Reason

Note: Read the Assertion (A) and Reason (R) carefully to mark the correct option out of the options given below:
a. If both assertion and reason are true and the reason is the correct explanation of the assertion.
b. If both assertion and reason are true but reason is not the correct explanation of the assertion.
c. If assertion is true but reason is false.
d. If the assertion and reason both are false.
e. If assertion is false but reason is true.

Question. Assertion: All F – S – F angle in SF₄ greater than 90° but less than 180°
Reason: The lone pair-bond pair repulsion is weaker than bond pair-bond pair repulsion
Answer : C

Question. Assertion: Water is liquid but H₂S is a gas.
Reason: Oxygen is paramagnetic.
Answer : B

Question. Assertion: The fluorine has lower reactivity.
Reason: F – F bond has low bond dissociation energy.
Answer : C

Question. Assertion: Nitrogen molecule diamagnetic.
Reason: N₂ molecule have unpaired electrons.
Answer : C

Question. Assertion: Ice is less dense than liquid water.
Reason: There are vacant spaces between hydrogen bonded water molecules in ice.
Answer : A

Question. Assertion: Born-Haber cycle is based on Hess’s law.
Reason: Lattice enthalpy can be calculated by Born- Haber cycle.
Answer : B

Question. Assertion: Iodine is more soluble in water then in carbon tetrachloride.
Reason: Iodine is a polar compound.
Answer : D

Question. Assertion: o and p-nitrophenols can be separated by steam distillation.
Reason: o-nitrophenol has intra-molecular hydrogen bonding while p-nitrophenol exists as associated molecules.
Answer : A

Question. Assertion: Electron affinity refers to an isolated atom’s attraction for an additional electron while electro-negativity is the ability of an element to attract electrons towards itself in a shared pair of electrons.
Reason: Electron affinity is a relative number and electronegativity is experimentally measurable.
Answer : C

Question. Assertion: Geometry of SF₄ molecule can be termed as distorted tetrahedron, a folded square or see saw.
Reason: Four fluorine atoms surround or form bond with sulphur molecule.
Answer : B

Comprehension Based

Paragraph

Dipole moment of a bond is a vector and physical quantity to calculate the percentage ionic character in a covalent bond. It is expressed as Dipole moment (μ) = δ × 4
Where, δ is dipole moment and d is the bond length.
It is usually expressed in terms of CGS unit known ad Debye
(D)1D= 10^–18 esu cm. In SI unit it is expressed in Coulomb meter. Resultant dipole moment  (μ_R) of two bond moment (μ₁ and μ₂) acting at angle θ, is given by: μ_R = √μ²₁+ μ²₂ + 2μ₁μ₂ cosθ
If μ₁ = μ₂ , also if cos θ = 1, i.e., θ =180° then μ = 0
(molecule is nonpolar) If μ ≠ 0 molecule is polar.
Dipole moment plays an important role in deciding the stability order of alkanes, i.e., a more stable alkane has less dipole moment. The dipole moment of a molecule can predict the geometrical and position isomers as well as orientations in benzene nucleus and polarity of molecule.

Question. Dipole moment of HCl molecule is found to be 0.186 D. Assuming HCl bond length to be equal to 1Å, the % ionic character of HCl molecule is:
a. 10%
b. 17%
c. 27%
d. 37
Answer : B

Question. The correct increasing order of dipole moment of the following compounds is:
(I) toluene (II) o-dichlorobenzene
(III) m-dichlorobenzene (Iv) p-dichlorobenzene
a. I < II < III < IV
b. IV < I < III < II
c. I < IV < III < II
d. IV < I < II < II
Answer : B

Question. Dipole moment of (1) p-dinitrobenzene, (2) p-dichlorobenzene and (3) p-dimethoxybenzene are in the order:
a. 3 > 2 > 1
b. 3 = 2 > 1
c. 3 = 2 = 1
d. 3 > (2 = 1)
Answer : D

Question. Identify the correct increasing order of the stability of thefollowing alkenes, (I) cis-2-butene; (II) trans-2-butene; (III) Isobutene:
a. II < III < I
b. I < III < II
c. I < II < III
d. III < II < I
Answer : D

Question. Which of the following species is no polar?
a. Ammonia
b. Sulphur dioxide
c. Water
d. Sulphur trioxide
Answer : D

Question. The increasing order of dipole moment of bond in halogen acids is:
a. HF > HCl >HBr> HI
b. HI > HCl >HBr> HF
c. HCl > HBr >HIr> HF
d. HI > HBr >HF> HCl
Answer : A

Question. Which molecular is non-polar?
a. trans-Pent-2-ene
b. cis-Pent-2-ene
c. cis-1-chloroporopne
d. SF₆
Answer : D

Question. Which species is polar?
a. trans-Hex-3-ene
b. trans-But-2-ene
c. PCl₅
d. XeF₆
Answer : D

Integer

Question. The total number of lone-pairs of electrons in melamine is:
Answer : 6

Question. The number of lone pairs in 4 BF− is …………….
Answer : 12

Question. The maximum number of atoms that may lie in the same plane in (CH₃)₂C = SF₂ (CH₃)₂ is …………….
Answer : 8

Question. The sum of oxidation states of N atoms in the following compounds of nitrogen is ………......…….NH₃, N₂H₄, NH₂OH, N₂, N₂O, NO, N₂O₃, NO₂, N₂O₅.
Answer : 9

Question. The number of nodal planes when two d_xy orbitals from two atoms produce antibonding δ bonds is
Answer : 3

Question. Based on VSEPR theory, the number of 90° F − Br − F angles in BrF₅ is:
Answer : 0

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