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Chemical Bonding and Molecular Structure

Multiple Choice Questions

821.

Hydrofluoric acid shows hydrogen bonding due to :

high electron affinity of fluorine
high bond dissociation energy of fluorine
high electronegativity of fluorine
none of the above

822.

Assertion: The S-S-S bond angle in S₈ molecule is 105°.

Reason : S₈ has a V-shape.

If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false

823.

Assertion : Sodium formate has both the C-O bonds have same value 1.27Å.

Reason : Equal bond length is due to the phenomenon of resonance.

If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false

824.

Ionic compounds are formed most easily with :

low electron affinity , high ionisation energy
high electron affinity , low ionisation energy
low electron affinity , low ionisation energy
high electron affinity , high ionisation energy

825.

The order of bond length is

O₂ < O₃ < O $_{2}^{2 -}$
O₂ < O $_{2}^{2 -}$ < O₃
O $_{2}^{2 -}$ < O₃ < O₂
O₂ = O $_{2}^{2 -}$ > O₃

826.

The correct order of dipole moment is

CH₄ <NF₃<NH₃<H₂O
NF₃ <CH₄ <NH₃ <H₂O
NH₃ <NF₃ <CH₄ <H₂O
H₂O <NH₃ <NF₃<CH₄

827.
Which of the following is paramagnetic ?

N₂

C₂

N₂⁺

O₂^2-

N₂⁺

C₂ ➔ the molecular orbital configuration (12) is

➔ C₂ = [( $σ$ 1s)² ( $\overset{*}{σ}$ 1s)² ( $σ$ 2s)² ( $\overset{*}{σ}$ 2s)² ( $π$ 2p_y)² ( $π$ 2p_z)²]

C₂ molecule is diamagnetic as it does not contain any unpaired electron

N₂ ➔ the molecular orbital configuration (14) is

➔ N₂ = [( $σ$ 1s)² ( $\overset{*}{σ}$ 1s)² ( $σ$ 2s)² ( $\overset{*}{σ}$ 2s)² ( $π$ 2p_y)² ( $π$ 2p_z)² ( $σ$ 2p_x)²]

N₂ molecule is diamagnetic because it does not contain any unpaired electron .

N₂⁺ ➔ the molecular orbital configuration (13) is

➔ N₂⁺ = [( $σ$ 1s)² ( $\overset{*}{σ}$ 1s)² ( $σ$ 2s)² ( $\overset{*}{σ}$ 2s)² ( $π$ 2p_y)² ( $π$ 2p_z)² ( $σ$ 2p_x)¹]

N₂⁺ molecule is paramagnetic because it contain one unpaired electron .

O₂^2- ➔ the molecular orbital configuration (18) is

➔ O₂^2- = [( $σ$ 1s)² ( $\overset{*}{σ}$ 1s)² ( $σ$ 2s)² ( $\overset{*}{σ}$ 2s)² ( $σ$ 2p_x)² ( $π$ 2p_y)² ( $π$ 2p_z)² ( $\overset{*}{π}$ 2p_y)² ( $\overset{*}{π}$ 2pz)2]

It does not contain any unpaired electron so , it is diamagnetic .

828.

Assertion : SeCl₄ does not have a tetrahedral structure.

Reason : Se in SeCl₄ has two lone pairs.

If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.