Question

Give reason : when copper turnings are put in green ferrous sulphate solution,there is no colour change?

Answer 1

This happens due to the fact that Copper (Cu) is less reactive than Iron (Fe). Thus, it is unable to displace the iron ions from the solution.

Answer 2

When copper turnings are put in green ferrous sulphate solution, there is no colour change due to less reactivity of copper than iron.

• In the reactivity series, copper is placed below iron in reactivity series. This states the reactive nature of iron and the unreactive nature of copper.
• Thus, when copper comes in contact with ferrous sulphate solution, the reaction does not occur. Subsequently, colour change also does not take place.
• On the other hand, if the iron nail is placed in copper sulphate solution, the reaction occurs.
• Iron displaces copper ions thus changing blue colour to green forming iron sulphate.
• The balanced chemical reaction expressing the conversion is as follows - CuSO4 + Fe --> Cu + FeSO4. In this chemical reaction, CuSO4 is copper sulphate, Fe is iron, Cu is copper and FeSO4 is iron sulphate.

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