Easy MCQ +4 / -1 PYQ · JEE Mains 2021

On treating a compound with warm dil. H2SO4, gas X is evolved which turns K2Cr2O7 paper acidified with dil. H2SO4 to a green compound Y. X and Y respectively are :

  1. A X = SO<sub>2</sub>, Y = Cr<sub>2</sub>O<sub>3</sub>
  2. B X = SO<sub>3</sub>, Y = Cr<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>
  3. C X = SO<sub>3</sub>, Y = Cr<sub>2</sub>O<sub>3</sub>
  4. D X = SO<sub>2</sub>, Y = Cr<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub> Correct answer

Solution

SO<sub>2</sub> + K<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub> + dil. H<sub>2</sub>SO<sub>4</sub> $\to$ SO<sub>3</sub> + Cr<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub> (green)

About this question

Subject: Chemistry · Chapter: p-Block Elements · Topic: Group 13: Boron Family

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