Calcium chloride can serve as a source of calcium ions in an aqueous solution, as calcium chloride is soluble in water. This property can be useful for displacing ions from solution. For example, phosphate is displaced from solution by calcium:
3 CaCl2(aq) + 2 K3PO4(aq) → Ca3(PO4)2(s) + 6 KCl(aq)
Molten calcium chloride can be electrolysed to give calcium metal and chlorine gas:
CaCl2(l) → Ca(s) + Cl2(g)
Calcium chloride has a very high enthalpy change of solution. A considerable temperature rise accompanies its dissolution in water.
The anhydrous salt is deliquescent; it can accumulate enough water in its crystal lattice to form a solution.
