Question

Which of the following trihalides is not hydrolysed by water?

• A. $N{F}_3$
• B. $NC{l}_3$
• C. $PC{l}_3$
• D. $AsC{l}_3$

Answer 1

The correct option is A $N{F}_3$

In the hydrolysis of a trihalide by water molecules, the lone pairs on the oxygen atom react with the vacant orbitals of the atoms present in the compound.
In $N{F}_3$, both $N$ and $F$ do not have any vacant orbitals and so $N{F}_3$ cannot be hydrolysed by water molecules. All other trihalides in the options can be hydrolysed as they have vacant orbitals to accept the lone pairs on the oxygen atom of the water molecule.