The boiling points of some group 7a hydrides are tabulated below.
gas b. p. (°c)
nh3 –33
ph3 –88
ash3 –62
which intermolecular force or bond is responsible for the high boiling point of nh3 relative to ph3 and ash3? a) dipole/induced dipole force b) covalent bonding c) dipole-dipole force d) induced dipole/induced dipole force e) hydrogen bonding

hey there!:

In the case of ammonia, the hydrogen bond is formed using the lone pair present in nitrogen and the hydrogen having δ+ charge (due to bonding with electronegative N) of another ammonia molecule. Thus the inter molecular attraction increases which in turn increases the boiling point .

Option B is the correct answer.

Hope this helps!

i just learnt this recently but i need to look through my notes again