The `BCl_3` is a planar molecule whereas `NCl_3` is pyramidal because

Options

A. N-Cl bond is more covalent than B-Cl bond
B. B-Cl bond is more polar than N-Cl bond
C. Nitrogen atom is smaller than boron
D. `BCI_3` has no lone pair but `NCl_3`, has a lone pair of electron

Answer

D

Explanation

` BCI_3` is `sp^2` hybridised hence planar whereas `NCl_3` is` sp^3 `hybridised with one Ip, hence is pyramidal.