What is the $pH$ of $10 \ L$ of a buffer solution containing $0.01 \ M \ NH_4Cl$ and $0.1 \ M \ NH_4OH$ having $pK_b$ of $5$?

The $K_b$ of $NH_4OH$ is $1.8 \times 10^{-5}$. Calculate the $pH$ of a solution containing $0.15 \ M$ $NH_4OH$ and $0.25 \ M$ $NH_4Cl$.

Find the $pH$ when $0.2 \, mol$ of $HCl$ is added to $1 \, L$ of a solution containing $1 \, M$ $CH_3COOH$ and $1 \, M$ $CH_3COO^-$. Assume the total volume remains $1 \, L$. Given $K_a$ for $CH_3COOH = 1.8 \times 10^{-5}$.

Which among the following pairs constitutes a buffer?

The $pK_a$ of a weak acid $(HA)$ is $4.5$. The $pOH$ of an aqueous buffer solution of $HA$ in which $50\%$ of the acid is ionized is

$A$ buffer solution has equal volumes of $0.2 \ M \ NH_4OH$ and $0.02 \ M \ NH_4Cl$. The $pK_b$ of the base is $5$. The $pH$ is