Which of the following oxoacids of phosphorus contain at least one reducing bond in their chemical s — p Block Elements Chemistry Question

💡 Solution & Explanation

$H_3PO_3$ has one $P-H$ bond. $H_3PO_2$ has two $P-H$ bonds. Pyrophosphorous acid ($H_4P_2O_5$) features two $P-H$ bonds (one on each P atom). Hypophosphoric acid ($H_4P_2O_6$) contains four $P-OH$ bonds, two $P=O$ bonds, and one $P-P$ bond, but zero $P-H$ bonds.