Question

Select correct statements(s) (A) $\text{NF}_3$ has more dipole moment than $\text{NH}_3$ (B) $\text{O}_2^{2-}$ and $\text{F}_2$ both have same bond order (C) In $\text{O}_3$ central oxygen atom has $+1$ formal charge (D) In $\text{NO}_2$ all the atoms follow octet rule, so it is stable. (E) $\text{BeH}_2$ is planar

• A. B, C
• B. A, B, C
• C. C, D, E
• D. B, E

Hint:

Pay close attention to dipole moment cancellation in pyramidal molecules ($\text{NF}_3$ vs $\text{NH}_3$). Use $\text{MO}$ theory for accurate bond order comparison of diatomic species.

Answer 1

The Correct Option is D

(A) $\mu(\text{NF}_3)<\mu(\text{NH}_3)$ because bond dipoles in $\text{NF}_3$ partially cancel the lone pair dipole. (A) is Incorrect.
(B) $\text{O}_2^{2-}$ ($\text{BO}=1$) and $\text{F}_2$ ($\text{BO}=1$). (B) is Correct.
(C) $\text{O}_3$ central $\text{O}$ has $1 \text{ LP}$ and 3 bonds. $\text{FC}=6-2-1/2(6)=+1$. (C) is Correct.
(D) $\text{NO}_2$ is an odd electron species (17 $\text{VE}$) and violates the octet rule. (D) is Incorrect.
(E) $\text{BeH}_2$ is $sp$ hybridized (Linear), which is planar. (E) is Correct.