Question

A group 15 element, which is a metal and forms a hydride with strongest reducing power among group 15 hydrides. The element is :

• A. Sb
• B. $P$
• C. As
• D. Bi

Answer 1

Answer: (D)

In group $15$

Hydrides of group 15 elements are $N{H}_3$
$P{H}_3$
$As{H}_3$
$Sb{H}_3$
$Bi{H}_3$
In $N{H}_3$, hydrogen atom gets partial positive charge due to less electronegativity.

But in $Bi{H}_3$, hydrogen atom gets partial negative charge because hydrogen is more electronegative than bismuth.

i.e. $Bi{H}_3$ is a strong reducing agent than others because we know that $H^{-}$ is a strong reducing agent.