Liquid ammonia ionizes to a slight extent. At $-50°\mathrm{C}$, its ionization constant, ${\mathrm{K}}_{{\mathrm{NH}}_3}=\left[{\mathrm{NH}}_4^{+}\right]\left[{\mathrm{NH}}_2^{-}\right]={10}^{-30}$. How many amide ions are present per ${\mathrm{cm}}^3$ of pure liquid ammonia? Assume $\mathrm{N}=6.0\times {10}^{23}$.

When hydrogen chloride $\left(\mathrm{HCl}\right)$ is dissolved in acetic acid $\left({\mathrm{CH}}_3\mathrm{COOH}\right)$  then the following equilibrium is established like

${\mathrm{CH}}_3\mathrm{COOH} +\mathrm{HCl} \rightleftharpoons {\mathrm{CH}}_3{\mathrm{COOH}}_2^{+} + {\mathrm{Cl}}^{-}$ 

Which of the following set is correct respective to conjugate acid-base pair ?

$\mathrm{BOH}$ is a weak base. The molar concentration of $\mathrm{BOH}$ that provides an $\left[{\mathrm{OH}}^{-}\right]$ of $1.5\times {10}^{-3} \mathrm{M}$ is

$\left[{\mathrm{K}}_{\mathrm{b} }\left[\mathrm{BOH}\right]=1.5\times {10}^{-5} \mathrm{M}\right]$