Question

Which of the following molecule have only one $p\pi -d\pi$ bond and zero $p\pi -p\pi$ bonds?

• A. $Cl{O}_3^{-}$
• B. $S{O}_2$
• C. $Cl{F}_3$
• D. $S{O}_3^{2-}$

Answer 1

The correct option is D $S{O}_3^{2-}$

(A) $Cl{O}_3^{-}$
$C{l}^{\ast }=\left[Ne\right]3s^{2}3p^{3}3d^2$
The three electrons in $3p$ orbital form $\sigma$ bond and the two electrons in d-orbital are responsible for formation of $\pi$ bond.

$\therefore 2p\pi -d\pi$
$0p\pi -p\pi$

(B) $S{O}_2$
$S^{\ast }=\left[Ne\right]3s^{2}3p^{3}3d^1$
One electrons from $3p$ orbital and one electron from d-orbital are responsible for formation of $\pi$ bond.

$1p\pi -d\pi$
$1p\pi -p\pi$

(C) $Cl{F}_3$
In this molecule no $\pi$ bond is formed.

$0p\pi -d\pi$
$0p\pi -p\pi$

(D) $S{O}_3^{2-}$
$S^{\ast }=\left[Ne\right]3s^{2}3p^{3}3d^1$
The three electrons in $3p$ orbital form $\sigma$ bond and one electron in d-orbital is responsible for formation of $\pi$ bond.


$1p\pi -d\pi$
$0p\pi -p\pi$