Hydrogen sulfide is a colorless gas with a characteristic smell resembling rotten eggs. At high concentrations it is toxic. Paraffin and sulfur react under heating producing hydrogen sulfide and carbon. This reaction is more convenient compared to the reaction of sulfides with diluted acid since it allows controlling the gas flow precisely. Addition of diluted acid to iron or zinc sulfide also leads to release of hydrogen sulfide in a double exchange reaction. The solution of hydrogen sulfide in water is a very weak acid. That is why acid base indicators change their color according to pH shift. For example litmus turns red in solution of hydrogen sulfide. The reaction of hydrogen sulfide water with copper sulfate is analogous to the well-known qualitative reaction on hydrogen sulfide with lead ions. Just as lead, copper sulfate forms an insoluble black precipitate of copper sulfide. We are specialty gases manufacturer in China, we can supply varies of gases including hydrogen sulfide.
