the reactants for the equation NaCl + CaS the products of the reaction Na₂S + CaCl₂ this a double displacement reaction where the cations of one salt form new salts with the anion of the other salt and vice versa. the balanced reaction therefore ; 2NaCl + CaS ---> Na₂S + CaCl₂ a0 - 2 a1 - 1 a2 - 1 a3 - 1