CBSE 2025 · Region 1 · Set 2 · Q18 · 2 marks

When $\displaystyle \mathrm{FeCr}_{2} \mathrm{O}_{4}$ is fused with $\displaystyle \mathrm{Na}_{2} \mathrm{CO}_{3}$ in the presence of air it gives a yellow solution of compound (A). Compound (A) on acidification gives compound (B). Compound (B) on reaction with KCl forms an orange coloured (C). An acidified solution of compound (C) oxidises iodide to (D). Identify (A), (B), (C) and (D).

CBSE Class 12 Chemistry past-paper question from the 2025board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.