Question

Give a chemical test to distinguish between the following gases:

Chlorine and nitrogen dioxide

Answer 1

Chlorine [Cl₂]:

1. Moist litmus [blue] turns red and gets bleached,
2. Turns moist starch iodide paper blue black.

Nitrogen dioxide [NO₂]:

1. Turns blue litmus red.
2. Displaces I₂ from KI and turns potassium iodide paper brown.