Equal volumes of $0.1. \mathrm{M}$ aniline solution $\left({\mathrm{K}}_{\mathrm{b}}={10}^{-10}\right)$ are mixed with$0.1 \mathrm{M} {\mathrm{NH}}_3$ the solution $\left({\mathrm{K}}_{\mathrm{b}}={10}^{-6}\right)$. Then, which of the following is correct?

A diprotic, Carbonic acid has following the ${\mathrm{K}}_{\mathrm{a}}$ values.

$\begin{array}{ll}{\mathrm{H}}_2{\mathrm{CO}}_3+{\mathrm{H}}_2\mathrm{O}\rightleftharpoons {\mathrm{HCO}}_3^{-}+{\mathrm{H}}_3{\mathrm{O}}^{+},& {\mathrm{K}}_{\mathrm{a}1}=4.3\times {10}^{-7}\\ {\mathrm{HCO}}_3^{-}+{\mathrm{H}}_2\mathrm{O}\rightleftharpoons {\mathrm{CO}}_3^{-2}+{\mathrm{H}}_3{\mathrm{O}}^{+},& {\mathrm{K}}_{\mathrm{a}2}=4.8\times {10}^{-11}\end{array}$

What is the concentration of carbonate ion in saturated solution of ${\mathrm{H}}_2{\mathrm{CO}}_3$ that is $0.037\mathrm{M}$ ?

How many of the following are acidic salts?

${\mathrm{Na}}_2{\mathrm{SO}}_4 \mathrm{Ca}\left(\mathrm{OH}\right)\mathrm{Cl}$    $\mathrm{Pb}\left(\mathrm{OH}\right)\mathrm{Cl}$    ${\mathrm{NaHSO}}_4$

${\mathrm{NaHSO}}_3 {\mathrm{Na}}_2{\mathrm{SO}}_3$     ${\mathrm{Na}}_2\mathrm{S} \mathrm{BiOCl}$${\mathrm{NaH}}_2{\mathrm{PO}}_4$