05 Chemical Bonds
06 Acids, Bases and Salts
2 of 3

6.9.4 Preparing Insoluble Salts

Preparing Insoluble Salts

  1. Insoluble salts can be made by ionic precipitation (is also called double decomposition/double displacement).
  2. This involves mixing a solution that contains its positive ions with another solution that contains its negative ions.

Example:
Write the equation of the reaction that can be used to prepare the following salt:

  1. Calcium sulphate
  2. Lead chloride
  3. Copper carbonate

Answer:
a. Calcium sulphate

CaCl2 + NaSO4 → CaSO4 + 2NaCl
Ca(NO3)2 + ZnSO4 → CaSO4 + Zn(NO3)2

b. Lead chloride

Pb(NO3)2 + 2NaCl → PbCl2 + 2NaNO3

c. Copper carbonate

CuSO4 + Na2CO3 → CuCO3 + Na2SO4

CuCl2 + K2CO3 → CuCO3 + 2KCl
Cu(NO3)2 + Na2CO3 → CuCO3 + 2NaNO3