What is the value of $[H^{+}]$ when $0.1 \ mol$ of $CH_3NH_2$ is mixed with $0.08 \ mol$ of $HCl$? Given $K_b = 5 \times 10^{-4}$.

$A$ weak acid of dissociation constant $10^{-5}$ is being titrated with aqueous $NaOH$ solution. The $pH$ at the point of one-third neutralization of the acid will be:-

If $20 \ mL$ of $0.1 \ M \ NaOH$ is added to $30 \ mL$ of $0.2 \ M \ CH_3COOH$ $(pK_a = 4.74)$,find the $pH$ of the resulting solution.

When an acid or alkali is mixed with a buffer solution,the $pH$ of the buffer solution:

The approximate $pH$ of a solution formed by mixing equal volumes of $0.1 \ M$ sodium propanoate and $0.1 \ M$ propanoic acid (if the dissociation constant of propanoic acid is $1.3 \times 10^{-5}$) will be:

$A$ buffer solution is prepared by mixing $0.1 \ M \ HCN$ and $0.2 \ M \ NaCN$. What is the $pH$ of the buffer solution if $pKa$ of $HCN$ is $9.3$? $(\log 2 = 0.3010)$