How could you distinguish between #CO_2# from #H_2S#?

1 Answer
Nov 1, 2016


Odour would be the best bet.


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#.