Fundamental atomic and molecular processes, including surface collisions determining the density of hydrogen negative ions in a bounded hydrogen plasma, are summarized. The results of the model calculations based on the fundamental reaction processes in plasma volume and at the surface of the container wall are compared.with the experimental observations. The importance of the plasma-surface interaction in determining the density of negative ions in a bounded plasma is emphasized, and the discussion of the possible mechanism for the enhancement of the hydrogen negative ion density in a Cs introduced hydrogen discharge is given.