Explain the merits of generating H2S in the solution?

Question

Consult a reference book regarding the hazards associated with H2S. On the basis of this information, in which it is to be used. Briefly explain the chemistry involved in this generation.

Answer 1

H2S is toxic and smells revolting (rotten eggs).
If you can generate it in situ, so much the better.
It will be safer and much more pleasant for everybody in the laboratory!