Abstract:Mass transfer at hydrogen evolving mercury electrode has been studied by determining mass transfer coefficients of indicator ions as the function of current density of hydrogen evolution for various kinds of indicator ions in sulphuric acid solution. Mercury adhering to metal substrates of Ni, Cu or Ag is used as mercury electrode to overcome its trembling during the electrolysis. The effect of different indicator ions, electrode characteristic, substrate materiah diameter of electrode and temperature is examined. It is found that the mass transfer coemcient is proportional to the square root of current density of hydrogen evolution.

Key words: mercury  electrode  gas bubble  mass transfer