Exams › JEE Advanced › Chemistry
Correct answer: FeCl3
Two tests must both be positive: (1) Chromyl chloride test: positive only for chloride (Cl-) compounds — NaCl, CuCl2, FeCl3 pass; FeBr3 fails. (2) Blue color with potassium ferrocyanide K4Fe(CN)6: Fe3+ gives Prussian blue; Cu2+ gives chocolate/brown precipitate (not blue). Therefore FeCl3 satisfies both: it contains Cl- (chromyl chloride test positive) and Fe3+ (blue with K4Fe(CN)6). However, looking at the answer choices and the classic JEE question format, CuCl2 is often cited — but the correct chemistry points to FeCl3. Wait: Cu2+ + K4Fe(CN)6 gives a chocolate brown precipitate (Cu2[Fe(CN)6]). Fe3+ + K4Fe(CN)6 gives Prussian blue (Fe4[Fe(CN)6]3). So the correct answer is FeCl3.