Find the concentration of sodium acetate when added to $0.1 \ M$ solution of acetic acid to form a buffer solution of $pH = 5.5$ (in $M$)? $(pK_{a} \text{ of } CH_{3}COOH = 4.5)$

Find $pH$ of the resultant solution formed by the addition of $500 \ mL$ $0.1 \ M$ $Ba(OH)_2$ and $500 \ mL$ $0.6 \ M$ $NH_4Cl$ in $1 \ L$ pure $H_2O$ at $25 \ ^oC$ (Use $\log \ 2 = 0.3$,$\log \ 3 = 0.5$,$\log \ 5 = 0.7$,$K_b(NH_3) = 10^{-5}$)

The $pK_b$ of $CN^{\Theta}$ is $4.7$. The $pH$ of a solution prepared by mixing $2.5 \ mol$ of $KCN$ and $2.5 \ mol$ of $HCN$ in water and making the total volume up to $500 \ mL$ is:

$A$ solution of $0.1 \ mol$ of $CH_3NH_2$ $(K_b = 5 \times 10^{-4})$ and $0.08 \ mol$ of $HCl$ is diluted to $1 \ L$. The $pOH$ of the resulting solution is $(\log 1.25 = 0.1)$.

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

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