H3PO4 (phosphoric acid) is a strong acid that dissociates completely in water to form three H+ ions and one PO43- ion. The dissociation reaction is as follows:

H3PO4 (aq) → 3 H+ (aq) + PO43- (aq)

The three H+ ions produced by the dissociation of H3PO4 can each donate a proton to a water molecule, forming three H3O+ ions (hydronium ions). Thus, the overall dissociation of H3PO4 in water can be represented as follows:

H3PO4 (aq) + 3 H2O (l) → 3 H3O+ (aq) + PO43- (aq)