$0.2 \ M$ solution of formic acid is ionized $3.2 \%$. Its ionization constant is:

Calculate the ionisation constant of $0.08 \ mol \ dm^{-3}$ of a monobasic acid having $pH = 2$.

If two acids of equimolar concentration are taken,then which option is correct?

At $298 \ K$ temperature,calculate the $pH$ of a $0.25 \ M$ solution of $(CH_3)_2NH$ given that its $K_b$ is $5.4 \times 10^{-4}$.

$K_{a}$ for butyric acid $(C_{3}H_{7}COOH)$ is $2 \times 10^{-5}$. The $pH$ of $0.2 \ M$ solution of butyric acid is $........... \times 10^{-1}$. (Nearest integer) [Given $\log 2 = 0.30$]

Dimethyl amine $(CH_3)_2NH$ is a weak base and its ionization constant is $5.4 \times 10^{-5}$. Calculate $[OH^{-}]$,$[H_3O^{+}]$,$pOH$ and $pH$ of its $0.2 \ M$ solution at equilibrium.