Question

The dissociation constant of $N{H}_{4}OH$ is $1.8\times {10}^{-5}$. The hydrolysis constant of $N{H}_4^{+}$ ions at ${25}^{0}C$ would be:

• A. $5.556\times {10}^{-10}$
• B. $5.556\times {10}^{-11}$
• C. $7.556\times {10}^{-10}$
• D. $7.556\times {10}^{-11}$

Answer 1

The correct option is A $5.556\times {10}^{-10}$

The relationship betwen the hydrolysis constant of the salt ammonium chloride and the base dissociation constant of ammonia is as given below:
$K_h=\frac{K_w}{K_b}$
Substituting values in the above expression, we get:
$K_h=\frac{1\times {10}^{-14}}{1.8\times {10}^{-5}}=5.556\times {10}^{-10}$