Question

Why do the colour & solution of copper sulphate change when we take a solution of
copper sulphate in a beaker and put an iron nail in it?
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Answer 1

Answer:

When an iron nail immersed in the solution of copper sulphate than iron displaces copper from the solution of copper sulphate because iron is more reactive than copper. Therefore copper sulphate solution colour changes from blue to pale green.

Answer 2

Answer:

because it is a chemical reaction so the copper sulphate changes its colour when we put the iron nail