Q.Find out the structural formulae of various oxyacids of phosphorus.

Step 1. Recall orthophosphoric acid as the reference case. Section 9.7.7 describes H3PO4 as tetrahedral phosphorus bonded to one P=O and three P-OH groups, all three OH hydrogens ionizable — so it is triprotic.

Step 2. Compare other phosphorus oxyacids by basicity (number of ionizable P-OH groups, not total H atoms). In hypophosphorous acid, H3PO2, phosphorus is bonded to two P-H (non-ionizable) bonds, one P=O and only one P-OH, so it is monobasic despite having three hydrogens in its formula. In phosphorous acid, H3PO3, phosphorus is bonded to one P-H, one P=O and two P-OH groups, so it is dibasic. …

Extending the section 9.7.7 orthophosphoric-acid pattern to the other common phosphorus oxyacids using standard, well-establi …

• Counting every hydrogen in the formula as 'ionizable'; in H3PO2 and H3PO3, some hydrogens are bonded directly to phosphorus …