Question

write equation for successive dissociation of phosphoric acid

Answer 1

H3PO4(s) + H2O(l) ⇌ H3O+(aq) + H2PO−
4(aq)       Ka1 = 7.5×10−3H2PO−
4(aq) + H2O(l) ⇌ H3O+(aq) + HPO2−
4(aq)       Ka2 = 6.2×10−8HPO2−
4(aq) + H2O(l) ⇌ H3O+(aq) +  PO3−
4(aq)        Ka3 = 2.2×10−13