Brown ppt. (A) dissolve in HNO3 gives (B) which gives white ppt. (C) with NH4OH. (C) on reaction wit — Qualitative and Quantitative Analysis Chemistry Question
Question
Brown ppt. (A) dissolve in HNO3 gives (B) which gives white ppt. (C) with NH4OH. (C) on reaction with HCl gives solution (D) which gives white turbidity on addition of water. What is (D)?
💡 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).