(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 Iron nail is placed in a copper sulphate solution,  iron sulphate and copper are obtained. In this reaction, Iron displaces copper from copper sulphate compound. The blue colour of copper sulphate solution turns green due to the formation of zinc sulphate.

 This is a type of displacement reaction
 

(b) Barium chloride solution reacts with sodium sulphate solution to give insoluble barium sulphate and a solution of sodium chloride.

 $BaCl_{2}( aq) \ +\ Na_{2} SO_{4}( aq) \ \rightarrow BaSO_{4}( s) \ +\ 2NaCl( aq)$