Question

The bond length of $C-Cl$ in $C{H}_3-Cl$ is longer than that in chlorobenzene because:

• A. $Cl$ is attached to $s{p}^2$ hybridised $C$ atom in $C{H}_3-Cl$ and attached to $s{p}^2$ hybridised $C$ atom in chlorobenzene
• B. $Cl$ is attached to $s{p}^3$ hybridised $C$ atom in $C{H}_3-Cl$ and attached to $s{p}^2$ hybridised $C$ atom in chlorobenzene
• C. $Cl$ is attached to $s{p}^3$ hybridised $C$ atom in $C{H}_3-Cl$ and attached to $s{p}^3$ hybridised $C$ atom in chlorobenzene
• D. $Cl$ is attached to $s{p}^2$ hybridised $C$ atom in $C{H}_3-Cl$ and attached to $s{p}^3$ hybridised $C$ atom in chlorobenzene

Answer 1

The correct option is B $Cl$ is attached to $s{p}^3$ hybridised $C$ atom in $C{H}_3-Cl$ and attached to $s{p}^2$ hybridised $C$ atom in chlorobenzene

The $C-Cl$ bond length in chlorobenzene is shorter than in $C{H}_3-Cl$. As in chloromethane carbon attached to chloride is $s{p}^3$ hybridised.

While in chlorobenzene it is $s{p}^2$ hybridized. The delocalisation of electrons by resonance in chlorobenzene attribute for partial double bond character due to which bond length is shorter than a single bond. Hence, the correct answer will be option (b).