The P Block Elements - Result Question 31
####31. Of the following hybrides which one has the lowest boiling point?
[1989]
(a) $AsH_3$
(b) $SbH_3$
(c) $PH_3$
(d) $NH_3$
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Solution:
- (c) $NH_3$ undergoes H-bonding and hence has the highest b.p. Among the remaining hydrides i.e. $PH_3, AsH_3$ and $SbH_3$ the b.p. increases as the size of the element increases and hence the magnitude of the van der Waal’s forces of attraction increases. Thus, $PH_3$ has the lowest b.p.
