The correct option is **C. zinc is more electropositive than copper**. ### Detailed Explanation: 1. **Understanding the Reaction**: When excess zinc (Zn) is added to a solution of copper(II) sulfate (CuSO₄), a single displacement reaction occurs. In this reaction, zinc displaces copper from the copper(II) sulfate solution because zinc is more reactive (or more electropositive) than copper. The reaction can be represented as follows: \[ \text{Zn (s)} + \text{CuSO}_4 \text{(aq)} \rightarrow \text{Cu (s)} + \text{ZnSO}_4 \text{(aq)} \] Here, solid zinc reacts with aqueous copper(II) sulfate to produce solid copper and aqueous zinc sulfate. 2. **Why the Solution Becomes Colorless**: - The original solution of copper(II) sulfate is bluish-green due to the presence of copper(II) ions (Cu²⁺), which impart this characteristic color. - When zinc displaces copper, the copper ions are reduced to solid copper, which precipitates out of the solution. The remaining solution contains zinc ions (Zn²⁺) and sulfate ions (SO₄²⁻), which are colorless. Therefore, after filtering off the excess zinc and the precipitated copper, the resulting solution is colorless. 3. **Why Option C is Correct**: - Zinc is more electropositive than copper, meaning it has a greater tendency to lose electrons and form positive ions. This property allows zinc to displace copper from its compound (copper(II) sulfate) effectively. - The electropositivity of metals is a key factor in determining their reactivity. Since zinc can easily give up its electrons compared to copper, it can replace copper in the solution. ### Why the Other Options are Incorrect: - **Option A: Both zinc and copper are metals**: - While it is true that both zinc and copper are metals, this statement does not explain why the solution becomes colorless. The color change is due to the displacement reaction and the properties of the ions involved, not merely because both substances are metals. - **Option B: The sulphate radical and the zinc ion are divalent**: - This statement is misleading. While it is true that both the sulfate ion (SO₄²⁻) and the zinc ion (Zn²⁺) are divalent, this does not explain the color change of the solution. The color change is primarily due to the removal of copper ions, not the valency of the ions present. - **Option D: Both zinc and copper form depositive ions in solution**: - This statement is vague and does not address the specific reason for the color change. While both metals can form positive ions, the key factor in this reaction is the relative reactivity of zinc compared to copper, which is not mentioned in this option. ### Summary: - The reaction between zinc and copper(II) sulfate results in the displacement of copper due to zinc's higher electropositivity. - The bluish-green color of the copper(II) sulfate solution disappears because copper ions are removed from the solution as solid copper precipitates. - The remaining solution contains colorless zinc ions and sulfate ions, leading to a colorless solution after filtering. ### Revision Points: - Zinc displaces copper from copper(II) sulfate due to its higher electropositivity. - The color change from blue to colorless is due to the removal of copper ions. - The remaining ions in solution (Zn²⁺ and SO₄²⁻) are colorless. - Understanding the reactivity series of metals is crucial for predicting displacement reactions.