Upon passing $0.01 \mathrm{mole}$ $\mathrm{HCl}$ gas through $100 \mathrm{mL}$ of $0.05 \mathrm{M}$ Formic acid solution $\left({\mathrm{K}}_{\mathrm{a}}=1.8\times {10}^{-4}\right),$ determine change in $\mathrm{pH}$ of solution and $\left[{\mathrm{HCOO}}^{-}\right]$ in resulting solution.

For ortho phosphoric acid,

${\mathrm{H}}_3{\mathrm{PO}}_4\left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{aq}\right)⟶{\mathrm{H}}_3{\mathrm{O}}^{+}\left(\mathrm{aq}\right)+{\mathrm{H}}_2{\mathrm{PO}}_4^{-}\left(\mathrm{aq}\right); {\mathrm{K}}_{{\mathrm{a}}_1}$

${\mathrm{H}}_2{\mathrm{PO}}_4^{-}\left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{aq}\right)⟶{\mathrm{H}}_3{\mathrm{O}}^{+}\left(\mathrm{aq}\right)+{\mathrm{HPO}}_4^{2-}\left(\mathrm{aq}\right); {\mathrm{K}}_{{\mathrm{a}}_2}$

${\mathrm{HPO}}_4^{2-}\left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{aq}\right)⟶{\mathrm{H}}_3{\mathrm{O}}^{+}\left(\mathrm{aq}\right)+{\mathrm{PO}}_4^{3-}\left(\mathrm{aq}\right); {\mathrm{K}}_{{\mathrm{a}}_3}$

The correct order of ${\mathrm{K}}_{\mathrm{a}}$ values is:

In a solution of $0.1 \mathrm{M} {\mathrm{H}}_3{\mathrm{PO}}_4$ acid: (Given $\left.{\mathrm{K}}_{{\mathrm{a}}_1}={10}^{-3},{\mathrm{K}}_{{\mathrm{a}}_2}={10}^{-7},{\mathrm{K}}_{{\mathrm{a}}_3}={10}^{-12}\right)$

Concentration of ${\mathrm{H}}_3{\mathrm{PO}}_4$ is:

In a solution of $0.1 \mathrm{M} {\mathrm{H}}_3{\mathrm{PO}}_4$ acid: (Given $\left.{\mathrm{K}}_{{\mathrm{a}}_1}={10}^{-3}, {\mathrm{K}}_{{\mathrm{a}}_2}={10}^{-7}, {\mathrm{K}}_{{\mathrm{a}}_3}={10}^{-12}\right)$

Concentration of ${\mathrm{H}}_2{\mathrm{PO}}_4^{-}$ is:

In a solution of $0.1 \mathrm{M} {\mathrm{H}}_3{\mathrm{PO}}_4$ acid : (Given $\left.{\mathrm{K}}_{{\mathrm{a}}_1}={10}^{-3}, {\mathrm{K}}_{{\mathrm{a}}_2}={10}^{-7}, {\mathrm{K}}_{{\mathrm{a}}_3}={10}^{-12}\right)$

Concentration of ${\mathrm{HPO}}_4^{2-}$ is:

In a solution of $0.1 \mathrm{M} {\mathrm{H}}_3{\mathrm{PO}}_4$ acid: (Given $\left.{\mathrm{K}}_{{\mathrm{a}}_1}={10}^{-3}, {\mathrm{K}}_{{\mathrm{a}}_2}={10}^{-7}, {\mathrm{K}}_{{\mathrm{a}}_3}={10}^{-12}\right)$

Concentration of ${\mathrm{PO}}_4^{3-}$ is:

In a solution of $0.1 \mathrm{M} {\mathrm{H}}_3{\mathrm{PO}}_4$ acid: (Given $\left.{\mathrm{K}}_{{\mathrm{a}}_1}={10}^{-3}, {\mathrm{K}}_{{\mathrm{a}}_2}={10}^{-7}, {\mathrm{K}}_{{\mathrm{a}}_3}={10}^{-12}\right)$

$\mathrm{pH}$ of solution is: