JEE Advanced2021Chemistryp Block Elements (Group 15, 16, 17 & 18)Actual
Paragraph: The reaction of K ₃ [ Fe ( CN )₆ ] with freshly prepared FeSO ₄ solution produces a dark blue precipitate called Turnbull's blue. Reaction of K ₄ [ Fe ( CN )₆ ] with the FeSO ₄ solution in complete absence of air produces a white precipitate X , which turns blue in air. Mixing the FeSO ₄ solution with NaNO ₃ , followed by a slow addition of concentrated H ₂ SO ₄ through the side of the test tube produces a
Options
- AFe NO 2 SO 4 2 2 -
- BFe NO 2 H 2 O 4 3 +
- CFe NO 4 SO 4 2
- DFe NO H 2 O 5 2 +
Correct answer
D. Fe NO H 2 O 5 2 +
Step-by-step solution
3 Fe 2 + + NO 3 - + 4 H + → NO + 3 Fe 3 + + 2 H 2 O Fe H 2 O 6 2 + + NO → Fe H 2 O 5 NO 2 + Brown   ring + H 2 O