Question

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Why does the colour of copper sulphate solution change when
an iron nail is dipped in it?
Give an example of a double displacement reaction other than
the one given in Activity 1.10.
Identify the substances that are oxidised and the substances
that are reduced in the following reactions.
(i) 4Na(s) + 0,(g) → 2Na,O(s)
(ü) CuO(s) + H, (g) → Cu(s) + H, O(l)
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Answer 1

The colour of copper sulphate solution changes when an iron nail is dipped in it because iron is more reactive than copper. It displaces the colour of copper.