Question

The BCl₃ is a planar molecule whereas NCl₃ is pyramidal because

(a) nitrogen atom is smaller than boron atom

(b) BCl₃ has no lone pair but NCl₃ has a lone pair  of electrons

(c) B - Cl bond is more polar than N-Cl bond

(d) N - Cl bond is more covalent than B - Cl bond.

Answer 1

The correct option is: (b) BCl₃ has no lone pair but NCl₃ has a lone pair  of electrons

Explanation:

There is no lone pair on boron in BCl₃ hence no repulsion takes place. There is a lone pair on nitrogen in NCl₃ hence repulsion takes place. Therefore BCl₃ is planar molecule but NCl₃ is pyramidal molecule.