Reacting metal oxide with acid to form soluble salt

Steps:

• Identify copper(II) sulfate as CuSO4, needing a copper(II) source and sulfate ions without impurities.
• Evaluate options for reactions producing pure CuSO4 via displacement or acid-base.
• Eliminate non-reactive or impure methods using reactivity series and solubility rules.
• Select method yielding CuSO4 directly with filtration and crystallization for purity.

Why D is correct:

• CuO + H2SO4 → CuSO4 + H2O; insoluble oxide reacts completely with acid to form soluble CuSO4, filtered and crystallized pure.

Why the others are wrong:

• A: Cu below Zn in reactivity series; no displacement, no reaction.
• B: Cu metal inert to dilute H2SO4; no CuSO4 forms.
• C: No reaction between CuCO3 and Na2SO4; insoluble mixture, no CuSO4.

Final answer: D