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 K\(_{2}\)Cr\(_{2}\)O\(_{7}\) solution colourless

B.

acidified KMnO\(_{4}\) solution colourless

C.

Fe(NO\(_{3}\))\(_{2}\) solution green

D.

Pb(NO\(_{3}\))\(_{2}\) paper black

Correct answer is B

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