Question

The boiling points of the following hydrides follow the order of

• A. $\ce{SbH3 > NH3 > AsH3 > PH3}$
• B. $\ce{NH3 > AsH3 > PH3 > SbH3}$
• C. $\ce{SbH3 > AsH3 > PH3 > NH3}$
• D. $\ce{NH3 > PH3 > AsH3 > SbH3}$

Answer 1

Answer: (A)

$\ce{SbH3 > NH3 > AsH3 > PH3}$

Answer 2

Boiling point of $\ce{NH_3}$ is high due to intermolecular hydrogen bonding. In others it varies directly with molecular weight of molecule due to increased van der Wall�s force. This force is least in $\ce{PH_3}$ & highest in $\ce{SbH_3}$.