Purification of barium sulfate precipitate Steps:

• Precipitate BaSO4 by reacting BaCl2(aq) with Na2SO4(aq): Ba²⁺ + SO4²⁻ → BaSO4(s).
• Filter the mixture to isolate the solid BaSO4 from the solution.
• Wash the filter cake with distilled water to remove soluble impurities like NaCl.
• Heat the washed precipitate to dry it, yielding pure anhydrous BaSO4.

Why A is correct:

• "Heat filter wash" sequence ensures dryness and purity, as heating removes adsorbed water per standard gravimetric analysis protocol.

Why the others are wrong:

• B: Identical to A but likely refers to an incorrect reaction route lacking specificity for barium sulfate.
• C: Omits heating, leaving wet BaSO4 with impurities, violating purity requirements.
• D: No process specified, insufficient for any purification.

Not enough information for D's full details. Final answer: A