Calculate the $pH$ of a buffer solution containing $0.1 \text{ M } CH_3COOH$ and $0.1 \text{ M } CH_3COONa$ $[K_a = 1.8 \times 10^{-5}]$.

The $pH$ of a buffer solution made by mixing $25 \ mL$ of $0.02 \ M$ $NH_4OH$ and $25 \ mL$ of $0.2 \ M$ $NH_4Cl$ at $25^{\circ}C$ is ($pK_b$ of $NH_4OH = 4.8$).

$0.1 \ M$ formic acid solution is titrated against $0.1 \ M \ NaOH$ solution. What would be the difference in $pH$ between $1/5$ and $4/5$ stages of neutralization of acid?

Calculate $[H^{+}]$ of $0.2 \ M$ $HCN$ in $1 \ M$ $KCN$ solution. Given $K_{a(HCN)} = 4 \times 10^{-10}$.

Calculate the $pH$ of a buffer solution containing $6.1 \times 10^{-2} \ M$ sodium acetate $(CH_3COONa)$ in $1 \ L$ of $0.1 \ M$ acetic acid $(CH_3COOH)$ solution. (Given: $pK_a$ of $CH_3COOH = 4.76$)

Which of the following mixtures in water acts as a basic buffer?