The oxoacid of phosphorus that is easily obtained from a reaction of alkali and white phosphorus and has two P - H bonds, is

When white phosphorus ($$P_4$$) reacts with NaOH solution: $$P_4 + 3NaOH + 3H_2O \rightarrow PH_3 + 3NaH_2PO_2$$ the salt formed is sodium hypophosphite ($$NaH_2PO_2$$), which is the sodium salt of hypophosphorous acid ($$H_3PO_2$$), also known as phosphinic acid.

Phosphinic acid has phosphorus bonded directly to two hydrogen atoms (two P-H bonds), one P=O bond and one P-OH bond, so it has two P-H bonds, matching the given condition.

Among the other options, phosphonic acid ($$H_3PO_3$$) has only one P-H bond, hypophosphoric acid ($$H_4P_2O_6$$) has no P-H bonds, and pyrophosphorous acid ($$H_4P_2O_5$$) is not directly obtained from the reaction of $$P_4$$ with NaOH.

The correct answer is Option B: Phosphinic acid.