The boiling points of `NH_(3) , H_(2)O` and HF are higher than those of the hydrides of the subsequent members of the group. Give your reasons.

Explanation

The boiling points of `NH_(3),H_(2)O` and HF are higher than those of hydrides of the subsequent members of the group.
Reasons :
`toNH_(3),H_(2)OandHF` are electron rich hydrides and these have 1, 2 and 3 lone pairs respectively.
`to` Due to the presence of lonepairs on the high electronegative elements results in the formation of hydrogen bond [i.e. intermolecular hydrogen bonding].
`to` Due to the formation of hydrogen bond association of molecules takes place. Hence these hydrides has high boiling points.