Chemical Bonding And Molecular Structure Ques 93

Answer:

Correct Answer:68. (b)

Solution:

(b) In $SO_3^{-2}$

$S$ is $s p^{3}$ hybridised, so

$ _{16} S=1 s^{2} 2 s^{2} 2 p^{6} \underbrace{3 s^{2} 3 p_x^{1} 3 p_y^{1} 3 p_z^{1}} _{s p^{3} \text{ hybridisation }} \underbrace{3 d _{x y}^{1}} _{\text{unhybridised}} $

In ‘S’ unhybridized $d$-orbital is present, which will be involved in $\pi$ bond formation with oxygen atom.

$ _8 O=1 s^{2} 2 s^{2} 2 p^{4} $

In oxygen two unpaired $p$-orbitals are present in these one is involved in $\sigma$ bond formation while the other is used in $\pi$ bond formation

Thus in $SO_3^{2-}$, p $\pi$ and $d \pi$ orbitals are involved for $p \pi-d \pi$ bonding.