Question

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

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

Answer 1

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

Presence of bond pair and lone pair affects the shape of the molecule. This is because lone pairs and bond pairs repel each other and ultimately changes the shape of the molecule.

$BC{l}_3$	$3$ bond pairs and $0$ lone pair
$NC{l}_3$	$3$ bond pairs and $1$ lone pair

So the correct option is [D].