Hydrogen bonds are formed in many compounds e.g. `H_(2)O`, HF, `NH_(3)`. The boiling point of such compounds depends to a extent on the strength of hydrogen bond and the number of hydrogen bonds. The correct decreasing order of the boiling points above compounds is

Options

A. `HF gt H_2O gt NH_3`
B. `H_2O gt HF gt NH_3`
C. `NH_3 gt HF gt H_2O`
D. `NH_3 gt H_2O gt HF`

Answer

B

Explanation

Strength of H-bond is in the order
`H…….F gtH…….O gt H…….N`.
But each `H_2O` molecule is linked to four other `H_2O` molecules through H- bonds whereas each HF molecule is linked only to two other HF molecules.
Hence, b.p of `H_2O gt `b.p of `HF gt` b.p . of `NH_3`