JEE Main 2023Chemistryd and f Block ElementsHardMCQ

JEE Main 2023 — d and f Block Elements Question with Solution

JEE Main 2023 (24 Jan Shift 2)

Question

K2Cr2O7 paper acidified with dilute H2SO4 turns green when exposed to

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Show full solutionCorrect option: D
Correct answer
DSulphur dioxide

Step-by-step explanation

Carbon dioxide and sulphur trioxide cannot undergo oxidation. Potassium dichromate is reduced to chromic sulphate in the presence of sulphur dioxide. The orange solution of potassium dichromate becomes green colour chromic sulphate.

K2Cr2O7 + 3SO2 + H2SO4 → K2SO4 + Cr2(SO4)3 + H2O

Hence, the gas is sulphur dioxide.

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About this question

This is a previous-year question from JEE Main 2023, covering the d and f Block Elements chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.