electrolytes (0.01–0.5 M) on the electroreduction kinetics of ammonia complexes of nickel(II) at a dropping
mercury electrode is studied. The studies are conducted largely at low (about 2
10-5 M) concentrations of the nickel(II) complexes in the absence of the polarographic maximum (to eliminate the maximum, other authors
introduced surface-active substances). At [NH3] of 0.15–0.7 and 1–3 M, the slow electrochemical stage
involves, respectively, complexes Ni
and Ni
(k 
2) which form in
reversible conditions from complexes Ni
(i
= 3-6) predominant in solution. The half-wave potential shift in
the negative direc-tion, observed upon an increase in the supporting electrolyte concentration, is caused by the EDL structure. The
slow outer-sphere electrochemical stage involving two electrons yields nickel(0) complexes. Transfer coeffi-
cients and rate constants for the Ni
electroreduction are calculated.