In a solution,$0.02 \ M$ acetic acid is $4 \%$ dissociated. The $[OH^{-}]$ in the solution is

When $50 \ mL$ of $0.1 \ M$ $HCl$ and $50 \ mL$ of $0.2 \ M$ $NaOH$ solutions are mixed,the $pH$ of the resulting solution will be:

$A$ weak acid is titrated with a weak base. Consider the following statements regarding the $pH$ of the solution at the equivalence point.
$(i)$ $pH$ depends on the concentration of acid and base
$(ii)$ $pH$ is independent of the concentration of acid and base
$(iii)$ $pH$ depends on the $pK_{a}$ of acid and $pK_{b}$ of base
$(iv)$ $pH$ is independent of the $pK_{a}$ of acid and $pK_{b}$ of base
The correct statements are

On decreasing the $pH$ from $7$ to $2$,the solubility of a sparingly soluble salt $(MX)$ of a weak acid $(HX)$ increased from $10^{-4} \ mol \ L^{-1}$ to $10^{-3} \ mol \ L^{-1}$. The $pK_{a}$ of $HX$ is:

If the dissociation constant of a weak acid is $1.0 \times 10^{-5}$,then the equilibrium constant for its reaction with a strong base will be......

If $pK_{a} = -\log K_{a} = 4$ for a weak acid $HX$ and $K_{a} = C\alpha^{2}$,then the Van't Hoff factor when $C = 0.01 \ M$ is