Estimate the approximate $pK_a$ of $0.5 \ M$ $CH_3COOH$. Degree of dissociation (ionisation) is $0.15$ $(\log 1.32 = 0.12)$.

When $100 \ mL$ of $0.1 \ M$ $NaCN$ solution is titrated with $0.1 \ M$ $HCl$ solution,the variation of $pH$ of the solution with the volume of $HCl$ added will be:

If the concentration of $OH^{-}$ ions is $10^{-7} \text{ gram ions/litre}$,what is the number of $OH^{-}$ ions in one litre of water?

What will be the change in acidity if
$(i)$ $CuSO_4$ is added in saturated $(NH_4)_2SO_4$ solution
$(ii)$ $SbF_5$ is added in anhydrous $HF$?

Equal volumes of aqueous solution of $0.1 \ M \ HCl$ and $0.2 \ M \ H_2SO_4$ are mixed. The concentration of $H^{+}$ ions in the resulting solution is (in $M$)

$A$ solution of $0.1 \ M$ weak base $(B)$ is titrated with $0.1 \ M$ of a strong acid $(HA)$. The variation of $pH$ of the solution with the volume of $HA$ added is shown in the figure below. What is the $pK_{b}$ of the base? The neutralization reaction is given by $B + HA \rightarrow BH^{+} + A^{-}$.