identify the type of chemical reaction taking place in each of the following:

1.barium chloride solution is mixed with copper sulphate solution and a white precipitate is observed.

2.on heating copper powder in air in a china dish,the surface of copper powder turns black.

3.on heating green coloured ferrous sulphate crystals,reddish brown solid is left and smell of gas having odour of burning sulphur is experienced.

4.iron nails when dipped in blue copper suplhate solution become brownish in colour and the blue colour of copper sulphate fades away.

5.quick lime reacts vigorously with water releasing a large amount of heat.