Which of the following mixtures of ions in solution can be separated by using NaOH solution? — Qualitative and Quantitative Analysis Chemistry Question

💡 Solution & Explanation

Step 1: This is the standard qualitative test for sulfide ions using sodium nitroprusside in alkaline media. Step 2: Sulfide ions (S2-) coordinate with sodium nitroprusside, [Fe(CN)5NO]2-, to yield a highly colored thionitrosyl complex: [Fe(CN)5NO]2- + S2- -> [Fe(CN)5NOS]4-. Step 3: This complex exhibits an intensely beautiful violet-purple color, corresponding to S2- in option (a).