Hydrogen Sulfide: Dilute Sulphuric Acid on Ferrous Sulfide, Collected over Hot Water (Thorpe 1912)

Pour dilute sulphuric acid on ferrous sulfide and hydrogen sulfide gas bubbles off: FeS + H2SO4 = FeSO4 + H2S. It is the usual laboratory way to make the gas. Result: hydrogen sulfide, never quite pure: specks of iron in the sulfide add some hydrogen. Source: Thorpe, Dictionary of Applied Chemistry, vol. 5 (1912), Sulphur. Not given: amounts, acid strength, apparatus. Danger: hydrogen sulfide is a deadly poison and it is flammable; make it only in a fume hood or outdoors. Picture drawn by Youblob.