A colourless inorganic compound (A) imparts a green colour to the flame. Its solution gives a white — Qualitative and Quantitative Analysis Chemistry Question
Question
A colourless inorganic compound (A) imparts a green colour to the flame. Its solution gives a white ppt. (B) with H2SO4. When heated with K2Cr2O7 and conc. H2SO4, a brown red vapour/gas (C) is formed. The gas/vapour when passed through aqueous NaOH solution, it turns into a yellow solution (D) which forms yellow precipitate (E) with CH3COOH and (CH3COO)2Pb. With reference to above information, answer the following questions.
💡 Solution & Explanation
Step 1: Separation of iron(III) hydroxide from aluminium hydroxide relies on their difference in amphoteric character. Step 2: Al(OH)3 is amphoteric and dissolves in excess sodium hydroxide (NaOH) to form soluble sodium aluminate (Na[Al(OH)4]), whereas Fe(OH)3 is purely basic and remains insoluble. Step 3: Therefore, adding NaOH solution successfully separates them by dissolving only Al(OH)3, leaving Fe(OH)3 as a precipitate, which matches option (c).