Question

Explain h3po3 is diprotic

Answer 1

As you can see the structure of orthophosphorus acid (or simply Phosphorous Acid) there are only two acidic Hydrogen (the ones attached to Oxygen) and therefore this compound is diprotic.

Answer 2

Answer: $H_3PO_3$ is diprotic as it can donate two hydrogen ions.

Explanation: Phosphorous acid $H_3PO_3$ is an acid as it dissolves in water to form hydrogen ions. It is diprotic means it donates two $H^+$ ions when dissolved in water though it contains three hydrogen atoms.

It is because only two of the hydrogen in $H_3PO_3$ are acidic which are bonded to oxygen. The hydrogen directly attached to phosphorous is not acidic and thus cannot be donated.