Question

Least volatile among the following is
a) NH3,
b) H2O
c) HF
d) PH3​

Answer 1

Answer:

H2O is least volatile due to strong H-bonding. 

It forms 2 hydrogen bonds. HF is also not much volatile but it forms only one hydrogen bond. 

Rest of the compounds are volatile since they do not have any hydrogen bonding.

Hence the correct option is C.