Question

In chlorobenzene C-CI bond length is 1.69 A° whereas as in ethyl choride C-CI bond length is 1.76A°.

Answer 1

In chlorobenzene, the compound undergoes resonance continuous to maintain stability which involves taking and giving back electrons to chlorine. Thus c-cl bond length is smaller.

In ethyl chloride, there is no resonance effect seen. Thus to maintain stability the bond length is slightly larger.