Chemistry - CHEMICAL BONDING Question with Solution | TestHub

The total number of diprotic acids among the following is $\begin{array}{lll}{\mathrm{H}}_3{\mathrm{PO}}_4& {\mathrm{H}}_2{\mathrm{SO}}_4& {\mathrm{H}}_3{\mathrm{PO}}_3\\ {\mathrm{H}}_2{\mathrm{CO}}_3& {\mathrm{H}}_2{\mathrm{S}}_2{\mathrm{O}}_7& {\mathrm{H}}_3{\mathrm{BO}}_3\\ {\mathrm{H}}_3{\mathrm{PO}}_2& {\mathrm{H}}_2{\mathrm{CrO}}_4& {\mathrm{H}}_2{\mathrm{SO}}_3\end{array}$