Purifying barium sulfate precipitate via standard lab procedure

Steps:

• Mix barium chloride and sodium sulfate solutions to precipitate insoluble BaSO4.
• Filter the mixture to collect the solid BaSO4 on filter paper.
• Wash the precipitate with distilled water to remove chloride and sulfate ions.
• Heat the washed precipitate gently to dry it, yielding pure anhydrous BaSO4.

Why A is correct:

• Heating removes adhered water molecules, producing dry, pure BaSO4 as required in gravimetric analysis for accurate mass determination.

Why the others are wrong:

• B. Filtering separates the precipitate but leaves impurities like excess ions attached.
• C. Washing eliminates soluble contaminants but results in a wet sample, not pure dry product.
• D. Not enough information (option incomplete).

Final answer: A