Question

The first acid ionization constant of the Oxoacids ${\mathbf{H}}_{\mathbf{3}}{\mathbf{PO}}_{\mathbf{2}}$is $\mathbf{8}\mathbf{\times }{\mathbf{10}}^{\mathbf{-}\mathbf{2}}$. What molecular structure do you predict for $\mathbf{8}\mathbf{\times }{\mathbf{10}}^{\mathbf{-}\mathbf{2}}$? In an aqueous solution, will this acid be monoprotic, diprotic, or triprotic?

Short answer

The structure of the acid is as shown below:

It is a monoprotic acid.

Step-by-step solution

The given oxyacid of phosphorus

The molecular formula of the given acid is ${\mathrm{H}}_3{\mathrm{PO}}_2$. It is a colorless low-melting compound soluble in water, dioxane, and alcohol.

Its structure is as shown below:

From the structure, it is clear that there is one basic hydrogen in the given acid.

Monoprotic acid

Based on the high value of the first acid ionization constant and its structure, the given acid is a monoprotic acid.