Question

The molecule in which an atom is associated with more than $8e^{-}s$ is known as hypervalent molecule. All hypervalent molecules must have $d\pi -p\pi$ bonding but the molecule having back bonding need not have always $d\pi -p\pi$ bonding.

Which of the following molecule is not having $d\pi -p\pi$ bonding?

• A. $S{O}_2$
• B. $P_4{O}_{10}$
• C. $H_{2}O$
• D. $B_3{N}_3{H}_6$

Answer 1

Answer: (C), (D)

$H_{2}O$
$B_3{N}_3{H}_6$

$S{O}_2,P_4{O}_{10}$ has $d\pi -p\pi$ bonding.

No, $d\pi -p\pi$ bonding exists in $H_{2}O$ and $B_3{N}_3{H}_6$.

In water, oxygen has a complete octet after forming the two bonds with hydrogen.

In $B_3{N}_3{H}_6$, there is an absence of d - orbitals in boron and nitrogen. Dative bond is formed between N and B atoms using p-orbitals of both.