Acidic buffer solution is prepared by mixing proportionate quantity of

The degree of dissociation of 0.01 M solution of $\mathrm{NH}_4 \mathrm{OH}$ is $4.2 \times 10^{-2}$. What is the percent dissociation of $\mathrm{NH}_4 \mathrm{OH}$ ?

Conjugate acid of $\mathrm{NH}_2^{-}$and $\mathrm{NH}_3$ are respectively

A buffer solution is prepared by mixing $0.2 \mathrm{~M} \mathrm{~NH} \mathrm{O}_4 \mathrm{OH}$ and $1 \mathrm{~M} \mathrm{~NH}_4 \mathrm{Cl}$. What is the pH value of buffer solution? $\left(\right.$ Give $\left.\mathrm{pK}_{\mathrm{b}}=7.744\right)$