The $\mathrm{pH}$ of an aqueous solution is Zero. The solution is

Identify the conjugate acid-base pair for the following reaction in aqueous solution. 

${\mathrm{HS}}^{-}\left(\mathrm{aq}\right) + \mathrm{HF}\left(\mathrm{aq}\right) \to {\mathrm{F}}^{-}\left(\mathrm{aq}\right) + {\mathrm{H}}_2\mathrm{S}\left(\mathrm{aq}\right)$

Identify the conjugate acid-base pair for the following reaction in aqueous solution. 

${\mathrm{HPO}}_4^{2-} + {\mathrm{SO}}_3^{2-} \to {\mathrm{PO}}_4^{3-} + {{\mathrm{HSO}}_3}^{-}$

Identify the conjugate acid base pair for the following reaction in aqueous solution.