Caption:
Barium sulphate precipitate, 3 of 3. Barium sulphate (BaSO4) precipitate formed by adding barium chloride solution (BaCl2) to copper sulphate solution (CuSO4). Both solutions are 0.5 M concentration. The reaction is CuSO4 + BaCl2 -> BaSO4 + CuCl2. This is an example of a double replacement reaction.