Question

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

• A. Nitrogen atom is smaller than boron atom
• B. $BC{l}_3$ has no lone pair but $NC{l}_3$ 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 $BC{l}_3$ has no lone pair but $NC{l}_3$ has a lone pair of electrons

There is no lone pair on boron in $BC{l}_3$ hence, no repulsion takes place. There is a lone pair on nitrogen in $NC{l}_3$ hence, repulsion takes place. Therefore, $BC{l}_3$ is planar molecule but $NC{l}_3$ is pyramidal molecule.