Question

Which of the following halides cannot be hydrolyzed?

(I) $Te{F}_6$, (II) $S{F}_6$, (III) $NC{l}_3$, and (IV) $N{F}_3$

• A. III and IV
• B. I, II and III
• C. I, II and IV
• D. II and IV

Answer 1

Answer: (D)

II and IV

Hydrolysis takes place through the coordination of lone pair of electron of $H_{2}O$ molecule. In case of ${NF}_3$, both nitrogen and fluorine do not have vacant d-orbitals to accept the lone pair. So ${NF}_3$ cannot be hydrolyzed.

For ${SF}_6$, it has $s{p}^3{d}^2$ hybridized molecule with octahedral geometry. It has zero dipole moment and is highly compact which repels incoming water molecules. So, it can not be hydrolyzed.

So, the correct answer is option D.