Question

H3PO2 is tribasic or dibasic

Answer 1

Answer: It is monobasic

Explanation: Ortho Phosphorous acid  $H_3PO_2$ is an acid as it dissolves in water to form hydrogen ions. It is monobasic means it donates oe $H^+$  ions when dissolved in water though it contains two hydrogen atoms.

It is because only one of the hydrogen in $H_3PO_2$ is acidic which is bonded to oxygen. The hydrogen directly attached to phosphorous is not acidic and thus cannot be donated.