Each of the following reactions is displayed to the right

 $\begin{array}{r}\mathrm{HCN}+{\mathrm{OH}}^{-}\rightleftharpoons {\mathrm{H}}_2\mathrm{O}+{\mathrm{CN}}^{-}\\ {\mathrm{H}}_3{\mathrm{PO}}_4+{\mathrm{CN}}^{-}\rightleftharpoons \mathrm{HCN}+{\mathrm{H}}_2{\mathrm{PO}}_4^{-}\end{array}$

Which of the following orders regarding acid strength is correct?

Solution:

Since the reactions are replaced to the right we will have $\mathrm{HCN}>{\mathrm{H}}_2\mathrm{O}\text{ and }{\mathrm{H}}_3{\mathrm{PO}}_4>\mathrm{HCN}$ 

Hence ${\mathrm{H}}_3{\mathrm{PO}}_4>\mathrm{HCN}>{\mathrm{H}}_2\mathrm{O}$

The molecules' hydrogen atoms give an acid its distinctive properties. Hydrogen atoms in strong acids are loosely bonded, which makes it simple for the molecules to dissociate in solution. The amount of these hydrogen atoms that split apart to generate hydrogen ions affects how potent an acid is.