Which has the lowest boiling point?

Options

A. `NH_(3)`
B. `PH_(3)`
C. `AsCl_(3)`
D. `SbH_(3)`

Answer

B

Explanation

In the hydrides of group 15, the boiling points changes as
`underset(238.5 K)(NH_(3)) gt underset(185.5K)(PH_(3))lt underset(210.6 K)(AsH_(3)) lt underset(254.6K)(SbH_(3)) lt underset(290 K)(BiH_(3))`
`:.` Generally mass increases then boiling point increases.
The higher point of `NH_(3)` is due to excessive hydrogen bonding, so `PH_(3)` have lowest boiling point among hydrides of group number `15`, i.e, nitrogen family.