Which one of the following statements is NOT correct for the given reaction? Fe(s) + CuSO 4 (aq) → FeSO 4 (aq) + Cu(s)
- A.Iron is the reducing agent
- B.The solution turns green in colour after the reaction
- C.Copper is a more reactive metal than iron
- D.The reaction is an example of a redox reaction
Correct answer
Explanation
The correct answer is C, Copper is a more reactive metal than iron. The reaction happens because iron is more reactive than copper and pushes it out of its salt, so statement C is false.
In this displacement reaction, an iron nail dipped in blue copper sulphate solution gets coated with brownish copper, and the solution slowly turns pale green as iron(II) sulphate forms. A more reactive metal can displace a less reactive one from its salt solution, and in the reactivity series iron stands above copper. Copper cannot displace iron from iron sulphate, which is why the reverse reaction does not occur.
A is correct because iron gives electrons to copper ions, going from 0 to +2, so it acts as the reducing agent.
B is correct because the blue colour of Cu²⁺ ions gives way to the pale green colour of Fe²⁺ ions.
D is correct because iron is oxidised and copper ions are reduced at the same time, which makes it a redox reaction.
Exam tip: iron nail in copper sulphate: blue turns green and copper deposits, because iron is above copper in the reactivity series.
Practice Questions
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