Colour of CrO4^2-(aq.) is not changed by : — Redox Reactions and Volumetric Analysis Chemistry Question

💡 Solution & Explanation

Step 1: Zinc sulfide, ZnS↓, is an insoluble white precipitate. Step 2: Addition of hydrochloric acid (HCl) decomposes the sulfide, releasing hydrogen sulfide gas (H2S↑) and forming soluble zinc chloride, ZnCl2. Step 3: Since the solid precipitate is dissolved to yield a clear soluble salt solution, this represents a precipitate dissolution reaction (type B), corresponding to option (b).