Clear solutions of Na₃PO₄(aq) and CaCl₂(aq) are mixed, producing a white solid. Which statement best classifies the chemical change that occurs?
a) It is a complex-ion formation reaction because Ca2+ coordinates with phosphate ligands in solution.
b) It is a precipitation reaction because Ca3(PO4)2(s) is insoluble in water.
c) It is an acid–base reaction because the base PO43− accepts protons from water supplied by Ca2+.
d) It is a redox reaction because Ca2+ is reduced to Ca metal while phosphorus is oxidised.