A white precipitate is obtained when: — Qualitative and Quantitative Analysis Chemistry Question

💡 Solution & Explanation

Step 1: The brown precipitate (A) is bismuth(III) sulfide (Bi2S3), which dissolves in HNO3 to give bismuth(III) nitrate (Bi(NO3)3, compound B). Treating this with NH4OH yields a white precipitate of bismuth(III) hydroxide (Bi(OH)3, compound C). Step 2: Reacting Bi(OH)3 with hydrochloric acid (HCl) dissolves the precipitate to yield a solution of bismuth(III) chloride (BiCl3, solution D). Step 3: When water is added to the BiCl3 solution, it hydrolyzes to form bismuth oxychloride (BiOCl), which precipitates as a white turbidity. Thus, solution (D) is BiCl3, corresponding to option (a).