Selective dissolution, filtration, and dehydration Steps:

• Dissolve mixture in water: hydrated CuSO₄·5H₂O dissolves, insoluble CaCO₃ remains undissolved.
• Filter solution: separates CaCO₃ residue, leaving CuSO₄ in filtrate.
• Evaporate water by gentle heating, then heat strongly to remove water of crystallization.
• Obtain pure, dry CuSO₄ (dehydrated form from original hydrate).

Why B is correct:

• CaCO₃ is insoluble in water (unlike soluble CuSO₄·5H₂O), so dissolution and filtration isolate CuSO₄; heating dehydrates to dry solid per lab procedure for anhydrous salt.

Why the others are wrong:

• A: Crystallisation yields wet hydrated crystals, not fully dry by removing all water.
• C: Distillation is unnecessary/irrelevant for separating solids; doesn't dissolve CuSO₄ first.
• D: Fractional distillation suits liquids/mixtures by boiling points, not solid salts like this.

Final answer: B