Question

In which of the following molecules the central atom does not retain any lone pair of electrons?

• A. $N{O}_2$
• B. $N{H}_3$
• C. $B{F}_3$
• D. $H_{2}O$

Answer 1

Answer: (C)

$B{F}_3$

Nitrogen and Oxygen atom is retained lone pairs in most of the compound but Boron has only $3$ electrons in its outer shell and even in $B{F}_3$ structure, the octet of boron is not complete, that's why the concept of back bonding takes place in $B{F}_3$.

So the correct option is $C$.