In an aqueous solution prepared by dissolving CuSO_4 in water, which of the following substances is the solute?

• A. Cu
• B. Fe
• C. FeSO_4
• D. CuSO_4

Answer: (D)

Verified step by step guidance

1. Understand the definition of solute and solvent: In a solution, the solute is the substance that is dissolved, and the solvent is the substance that does the dissolving (usually the component present in the largest amount).
2. Identify the components in the problem: The solution is prepared by dissolving CuSO_4 in water. Here, water is the solvent because it is the medium in which CuSO_4 dissolves.
3. Recognize that CuSO_4 is a compound that dissociates in water into ions (Cu^{2+} and SO_4^{2-}), but the entire compound CuSO_4 is considered the solute before dissociation.
4. Eliminate other options: Cu (copper metal) and Fe (iron metal) are not mentioned as being dissolved in the solution, and FeSO_4 is a different compound not involved in this solution.
5. Conclude that the solute in the aqueous solution is CuSO_4, as it is the substance dissolved in the solvent (water).