Question

Which of the following halides cannot be hydrolysed at room temperature?

$I.$ $Te{F}_6$ $II.$ $S{F}_6$ $III.$ $NC{l}_3$ $IV.$ $N{F}_3$

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

Answer 1

Answer: (D)

Here $S{F}_6$ cannot be hydrolysed at room temperature as in $S{F}_6,$ S-atom is sterically hindered by six fluorine atoms hence, attack of $H_{2}O$ molecule will not occur. $N{F}_3$ is not hydrolysed due to absence of vacant orbital on both N and F-atoms.

$Te{F}_6$ is hydrolysed due to large size of Te and presence of vacant d-orbital.