Find the $pH$ of a solution formed by mixing equal volumes of $0.1 \text{ M}$ sodium propionate and $0.1 \text{ M}$ propionic acid. (Given: The dissociation constant of propionic acid is $K_a = 1.3 \times 10^{-5}$)

Give the importance of buffer solution.

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

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 $\log \ 2 = 0.3$,$\log \ 3 = 0.5$,$\log \ 5 = 0.7$,$K_b(NH_3) = 10^{-5}$)

During the titration of $N/10$ acetic acid with $N/10 \, NaOH$,what is the $pH$ of the solution when $25\%$,$50\%$,and $75\%$ of the titration is complete? $[K_a = 10^{-5}]$

$A$ weak acid,$HA$,is found to be $10\%$ ionized in $0.01\ M$ aqueous solution. Calculate the $pH$ of a solution which is $0.1\ M$ in $HA$ and $0.05\ M$ in $NaA$.