(i) In chlorobenzene, due to resonance, there is a partial double bond character, so bond length is short.(ii) The dipole moment of chlorobenzene is lower as bond length is shorter $(\mu = q \times d)$ due to resonance and $\mathrm{sp}^2$ hybridized carbon, it has less tendency to release electrons than the $\mathrm{sp}^3$ hybrid of $\mathrm{C}-\mathrm{Cl}$ (in cyclohexyl chloride). Hence, chlorobenzene is more electronegative resulting in decrease in polarity of $\mathrm{C}-\mathrm{Cl}$ bond.