Identify the type of chemical reaction taking place and also write the balance chemical equation for :Iron nails when left dipped in blue copper sulphate solution, It becomes brownish in colour and the blue colour of copper sulphate fades away.

Q. You are given the following materials:
(i) Iron nails
(ii) Copper sulphate solution
(iii) Barium chloride solution
(iv) Copper powder
(v) Ferrous sulphate crystals
(vi) Quicklime

Identify the type of chemical reaction taking place when:
(a) Barium chloride solution is mixed with copper sulphate solution and a white precipitate is observed.
(b) On heating copper powder in air in a china dish, the surface of copper powder turns black.
(c) On heating green coloured ferrous sulphate crystals, reddish brown solid is left and smell of a gas having odour of burning sulphur is experienced.
(d) Iron nails when left dipped in blue colour copper sulphate solution become brownish in colour and the blue colour of copper sulphate fades away.
(e) Quick lime reacts vigorously with water releasing a large amount of heat.
Write chemical equations for each one of the above reactions.

Q. Explain why, the blue colour of copper sulphate solution fades when an iron nail is kept dipped in it. Write chemical equation of the reaction involved. What does this reaction tell us about the relative reactivities of copper and iron?

Q. (a) What happens when an aqueous solution of sodium sulphate reacts with an aqueous solution of barium chloride? State the physical conditions of reactants in which reaction between them will not take place. Write the balanced chemical equation for the reaction and also mention the type of reaction.

(b) What changes in the colour of iron nails and copper sulphate solution do you observe after keeping the iron nails in copper sulphate solution for about half an hour ?

Q. Copper sulphate is a blue coloured solution which undergoes a chemical change when iron nails are dropped inside it. Which amongst the given indicators will help to identify the chemical change taking place?