An oxide of phosphorus reacts with cold water to produce a dibasic acid. This acid can form exactly — p Block Elements Chemistry Question

💡 Solution & Explanation

The oxide $P_2O_3$ (or $P_4O_6$) reacts with water to form orthophosphorous acid ($H_3PO_3$). This acid is dibasic (having two $P-OH$ bonds and one non-ionizable $P-H$ bond). Upon neutralization with $NaOH$, it can form the primary salt $NaH_2PO_3$ and the secondary salt $Na_2HPO_3$.