Question

$BC{l}_3$ is a planar molecule, while $NC{l}_3$ is pyramidal, because :

• A. $N-Cl$ bond is more covalent than $B-Cl$ bond.
• B. Nitrogen atom is smaller than boron atom.
• C. $B-Cl$ bond is more polar than $N-Cl$ bond.
• D. $BC{l}_3$ has no lone pair of electrons but $NC{l}_3$ has a lone pair of electrons.

Answer 1

The correct option is D $BC{l}_3$ has no lone pair of electrons but $NC{l}_3$ has a lone pair of electrons.

$BC{l}_3$ has trigonal planar structure due to 3 bond pairs in the valence shell of boron where as $NC{l}_3$ has distorted tetrahedral structure (i.e., pyramidal structure) due to one lone pair and three bond pairs in the valence shell of nitrogen.