The $pK_a$ of a weak acid $(HA)$ and $pK_b$ of a weak base $(BOH)$ are $3.2$ and $3.4$ respectively. Find the $pH$ of their salt $(AB)$.

The dissociation constant of $NH_4OH$ is $1.8 \times 10^{-5}$. Calculate the hydrolysis constant of $NH_4Cl$.

Explain the following with reasons:
$(i)$ $NaCl$ solution is neutral. The solution of strong acid and strong base salts is neutral.
$(ii)$ $NaCH_3COO$ solution is basic. The solution of strong base and weak acid salt is basic.
$(iii)$ $NH_4Cl$ solution is acidic. The solution of weak base and strong acid salt is acidic.
$(iv)$ The solution of $NH_4CH_3COO$ is (almost) neutral. The solution of weak acid - weak base salts is almost neutral.

Which of the following relations is correct for a solution of $CH_3COONH_4$ salt? Concentration $0.001 \ M$,degree of hydrolysis $x_1$; Concentration $0.002 \ M$,degree of hydrolysis $x_2$.

The degree of hydrolysis of a $N/100$ $KCN$ solution is = ....... (Given $K_a = 1.4 \times 10^{-9}$)

$pH$ of a salt solution of weak acid $(pK_a = 4)$ and weak base $(pK_b = 5)$ at $25^{\circ}C$ is: