Question

Autoprotolysis constant of $N{H}_3$ is:

• A. ${[NH}_4^{+}\left]\right[{NH}_3]$
• B. ${[NH}_2^{-}\left]\right[{NH}_3]$
• C. ${[NH}_4^{+}\left]\right[{NH}_2^{-}]$
• D. ${[NH}_4^{+}\left]/\right[{NH}_2^{-}]$

Answer 1

Answer: (C)

${[NH}_4^{+}\left]\right[{NH}_2^{-}]$

The autoprotolysis of ammonia in its purest form can be represented as:

$2N{H}_3\rightleftharpoons N{H_2}^{-}+N{H_4}^{+}$

The autoprotolysis constant for the above reaction is given by:

$K_b=\left[{N{H}_2}^{-}\right]\left[{N{H}_4}^{+}\right]$