Question

Give a chemical test to distinguish following gases
(i) H₂ and O₂
(ii) CO₂ and SO₂

Answer 1

Chemical test to distinguish between given gases is given below -

For hydrogen and oxygen -

•The chemical test done to distinguish between these gases is burning splint test.

•Oxygen causes formation of high flames, when glowing splint is brought near.

•Hydrogen gas burns and pop sound is heard.

•This happens because hydrogen is flammable gas, and it explodes giving pop sound.

•Oxygen is not flammable gas but an oxidizer.

For CO2 and SO2 -

•Acidified potassium dichromate turns green in presence of sulphur dioxide, while no color change occurs in presence of carbon dioxide.

•This happens, because chromium has +6 oxidation state, in potassium dichromate and is orange in colour.

•On oxidation, +3 state is formed, which is green in color.

•Sulphur can donate electron, while carbon can not, because carbon is already in its highest oxidation state.