A colourless gas with a pungent smell is evolved when dilute hydrochloric acid is added to a sample of a salt. The gas evolved could turn?

A. acidified K₂Cr₂O₇ solution colourless
B. acidified KMnO₄ solution colourless
C. Fe(NO₃)₂ solution green
D. Pb(NO₃)₂ paper black

Correct Answer:

Option B – acidified KMnO₄ solution colourless

Explanation

If the potassium manganate(VII) solution is acidified with dilute sulfuric acid, the purple solution becomes colourless.