Question

You have a mixture of ${CO}_2,{SO}_2$ and $O_2$ gas. You have been provided following reagents for testing:

(A) lime water
(B) acidified potassium dichromate solution
(C) pyrogallol

Arrange these reagents in order such that only one gas is tested at one time.

• A. A, B, C
• B. B, C, A
• C. B, A, C
• D. A, C, B

Answer 1

The correct option is C B, A, C

The correct order is B, A and C.

Orange coloured acidified potassium dichromate solution will react with sulphur dioxide and is reduced to chromium sulphate which is green in colour.

Lime water $\left(CaO\right)$ will react with carbon dioxide will become white due to formation of calcium carbonate

Oxygen gas is soluble in alkaline pyrogallol solution.

Therefore, option C is correct.