The correct option for the question "The metal used to recover copper from a solution of copper sulphate is?" is **D. Fe (Iron)**. ### Detailed Explanation: 1. **Understanding the Reaction**: - The process of recovering copper from copper sulfate (CuSO₄) involves a displacement reaction. In a displacement reaction, a more reactive metal displaces a less reactive metal from its compound. - The general form of the reaction can be represented as: \[ \text{Metal (more reactive)} + \text{Copper Sulfate (CuSO}_4\text{)} \rightarrow \text{Copper (Cu)} + \text{Metal Sulfate (MetalSO}_4\text{)} \] 2. **Reactivity Series**: - To determine which metal can displace copper from copper sulfate, we refer to the reactivity series of metals. The reactivity series ranks metals from most reactive to least reactive. The order is generally: - Potassium (K) - Sodium (Na) - Calcium (Ca) - Magnesium (Mg) - Aluminum (Al) - Zinc (Zn) - Iron (Fe) - Lead (Pb) - Copper (Cu) - Silver (Ag) - Gold (Au) - From this series, we can see that iron (Fe) is more reactive than copper (Cu), which means it can displace copper from copper sulfate. 3. **The Reaction**: - When iron is added to a solution of copper sulfate, the following reaction occurs: \[ \text{Fe (s)} + \text{CuSO}_4\text{ (aq)} \rightarrow \text{Cu (s)} + \text{FeSO}_4\text{ (aq)} \] - In this reaction, solid copper (Cu) is produced, and iron sulfate (FeSO₄) remains in solution. ### Why the Other Options are Incorrect: - **A. Na (Sodium)**: - Sodium is indeed more reactive than copper, but it is not typically used in this context because it reacts violently with water and is not practical for this type of reaction in aqueous solutions. Sodium would react with water to produce hydrogen gas and sodium hydroxide, making it unsuitable for recovering copper from copper sulfate. - **B. Ag (Silver)**: - Silver is less reactive than copper. Therefore, it cannot displace copper from copper sulfate. In fact, if silver were added to the solution, no reaction would occur, and no copper would be recovered. - **C. Hg (Mercury)**: - Mercury is also less reactive than copper. Similar to silver, it cannot displace copper from copper sulfate. Thus, no recovery of copper would take place if mercury were used. ### Common Pitfalls: - Students may confuse the reactivity of metals and mistakenly choose a less reactive metal, thinking it can still displace copper. - It’s important to remember that the reactivity series is crucial for predicting the outcomes of displacement reactions. ### Revision Summary: - The metal used to recover copper from copper sulfate is **iron (Fe)**. - Iron is more reactive than copper, allowing it to displace copper in a solution. - Other metals like sodium, silver, and mercury are either too reactive (sodium) or less reactive (silver and mercury) to displace copper. - Always refer to the reactivity series when predicting displacement reactions in chemistry.