How could you distinguish between CO_2 from H_2S?

1 Answer
Nov 1, 2016

Odour would be the best bet.

Explanation:

Hydrogen sulfide, which is poisonous in large enough concentrations (mind you, so is CO_2, but here the concentration would be larger) has quite an offensive odour, which is quite distinctive.

Lead acetate paper is available commercially, and is used as a test for hydrogen sulfide, and gives a grey precipitate of lead sulfide. Carbon dioxide would fail this test.

H_2S(aq) + Pb(OAc)_2(aq) rarr PbS(s)darr + 2HOAc.