$A$ certain weak base has a dissociation constant $2 \times 10^{-5}$. The equilibrium constant for its neutralization reaction with a strong acid is

When $200 \ mL$ solution of $HCl$ of $pH=2$ is mixed with $300 \ mL$ solution of $NaOH$ of $pH=12$,the $pH$ of resulting solution is $(\log 2=0.3)$

$0.1 \ M$ solution of which of the following has almost unity degree of dissociation?

For the reaction in aqueous solution $Zn^{2+} + X^{-} \rightleftharpoons ZnX^{+}$,the $K_{eq}$ is greatest when $X$ is

The dissociation constants for acetic acid and $HCN$ at $25\,^{\circ}C$ are $1.5 \times 10^{-5}$ and $4.5 \times 10^{-10}$ respectively. The equilibrium constant for the equilibrium $CN^{-} + CH_3COOH \rightleftharpoons HCN + CH_3COO^{-}$ would be

The first and second ionization constants of a weak dibasic acid $H_{2}A$ are $8.1 \times 10^{-8}$ and $1.0 \times 10^{-13}$ respectively. $0.1 \text{ mol}$ of $H_{2}A$ was dissolved in $1 \text{ L}$ of $0.1 \text{ M}$ $HCl$ solution. The concentration of $HA^{-}$ in the resultant solution is: