Hydrogen sulfide, H2S(g), is a colourless, toxic, flammable gas. Its main use is in the qualitative inorganic analysis of certain metal ions. Hydrogen sulfide gas ionizes in water as shown below:
H2S(aq) + H2O (l) → H3O+(aq) + HS–(aq)
At equilibrium, which of the following statements is correct?
At equilibrium, the concentration of H2S(aq) remains constant.
This is because at equilibrium, the forward and reverse reactions occur at the same rate, resulting in a constant concentration of H2S(aq).