(a) What happens when a piece of iron metal is placed in copper sulphate solution? Name the type of reaction involved.
(b) Write balanced chemical equation with state symbols for the following reaction:
Barium chloride solution reacts with sodium sulphate solution to give insoluble barium sulphate and a solution of sodium chloride.

(a) When a piece of iron is placed in copper sulphate solution, it becomes brown in colour and the blue colour of the copper sulphate solution fades. This is because iron, being more reactive metal than copper, displaces copper from its solution.
Fe (s) + CuSO₄ (aq) → FeSO₄(aq) + Cu(s)
Thus, the type of reaction involved is displacement reaction.

(b) The balance chemical reaction is given as follows:
BaCl₂ (aq) + 2NaSO₄ (aq) → BaSO₄ (s) + 2NaCl (aq)