Question

Correct order of decreasing thermal stability is as

• A. $NH_{3} >\, PH_{3} >\, AsH_{3}>\, SbH_{3}$
• B. $PH_{3}>\, NH_{3}>\, AsH_{3}>\, SbH_{3}$
• C. $AsH_{3}>\, PH_{3}>\, NH_{3} >\, SbH_{3}$
• D. $SbH_{3}>\, AsH_{3}>\, PH_{3}>\, NH_{3}$

Answer 1

Answer: (A)

The thermal stability of the hydrides of nitrogen family or group $15$ elements decreases on moving downwards in the group. Therefore, $NH _{3}$ is the most stable and $BiH _{3}$ is the least stable. The stability of the hydrides of group $15$ elements decreases in the order
$NH _{3}> PH _{3}> ASH _{3}> SbH _{3}> BiH _{3}$