Question

The nitrogen atoms in $NH _3, NH _2^{-}$and $NH _4^{+}$are all surrounded by eight electrons. When these species are arranged in increasing of $H - N - H$ bond angle, correct order is

• A. $NH _3, NH _2^{-}, NH _4^{+}$
• B. $NH _4^{+}, NH _2^{-}, NH _3$
• C. $NH _3, NH _4^{+}, NH _2^{-}$
• D. $NH _2^{-}, NH _3, NH _4^{+}$

Answer 1

Answer: (D)

Repulsion $l p-l p l p-b p$
$l p-b p>b p-b p>b p-b p$
$b p-b p$
Due to repulsion, bond angle decreases
Bond angle $NH _2^{-}< NH _3< NH _4^{+}$