$A$ buffer solution is prepared by mixing $0.01 \ M$ $HCN$ and $0.02 \ M$ $NaCN$. If $K_{a}$ for $HCN$ is $6.6 \times 10^{-10}$,what is the concentration of $H^{+}$ ions in the solution?

One litre buffer solution was prepared by adding $0.10 \ mol$ each of $NH_3$ and $NH_4Cl$ in deionised water. The change in $pH$ on addition of $0.05 \ mol$ of $HCl$ to the above solution is $............ \times 10^{-2}$ ($Nearest$ $integer$) ($Given$: $pK_b$ of $NH_3 = 4.745$ and $\log_{10} 3 = 0.477$)

Which of the following mixtures will produce a buffer solution with $pH = 9$?

In order to prepare a buffer solution of $pH = 5.74$,sodium acetate is added to acetic acid. If the concentration of acetic acid in the buffer is $1.0 \ M$,the concentration of sodium acetate in the buffer is $......... \ M$. (Round off to the nearest integer).
[Given: $pKa$ (acetic acid) $= 4.74$]

$A$ certain buffer solution contains equal concentration of $X^{-}$ and $HX$. The $K_b$ for $X^{-}$ is $10^{-10}$. The $pH$ of the buffer is

The $pH$ of a buffer solution prepared by mixing $50 \ mL$ of $0.2 \ M$ $CH_3COOH$ and $250 \ mL$ of $CH_3COONa$ is $4.8$. What is the concentration of $CH_3COONa$ (in $M$)? Given that the $pKa$ of $CH_3COOH$ is $4.8$.