Question

Why `NF_3` cannot be hydrolysed, while `NCl_3` can be readily hydrolysed?

Answer 1

In `NH_3` atomic sizes of N and F are quite comparable and thus N-F bond is quite strong and `NF_3` is inert towards hydrolysis. Whereas atomic size of N and Cl vary much and `N-Cl` is much weak and `NCl_3` undergoes hydrolysis.