The initial rate of hydrolysis of methyl acetate $(1 \ M)$ by a weak acid $(HA, 1 \ M)$ is $1/100$th of that of a strong acid $(HX, 1 \ M)$ at $25^{\circ} C$. The $K_a$ of $HA$ is:

At $27^{\circ} C$,the degree of dissociation of $HA$ (weak acid) in $0.5 \ M$ of its solution is $1 \%$. The concentrations of $H_3O^{+}$,$A^{-}$,and $HA$ at equilibrium (in $mol \ L^{-1}$) are respectively

The dissociation constant of a weak acid is $1 \times 10^{-4}$. The equilibrium constant of its reaction with a strong base is:

At $25^{\circ} C$, the ionic product of water is $10^{-14}$. The free energy change for the self-ionization of water in $kCal \ mol^{-1}$ is close to

At $25^{\circ}C$, $20.0 \ mL$ of $0.2 \ M$ weak monoprotic acid $HX$ is titrated against $0.2 \ M$ $NaOH$. The $pH$ of the solution $(a)$ at the start of the titration (when $NaOH$ has not been added) and $(b)$ when $10 \ mL$ of $NaOH$ is added respectively, are:
Given: $K_a = 5 \times 10^{-4}, pK_a = 3.3, \alpha << 1$

The $pH$ of the solution containing $10 \ mL$ of $0.1 \ N$ $NaOH$ and $10 \ mL$ of $0.05 \ N$ $H_2SO_4$ would be