K2MnO4 + C2H5OH → MnO2 + CH3CHO + 2 KOH
This is an oxidation-reduction (redox) reaction:
MnVI + 2 e- → MnIV (reduction)
C-II - 3 e- → CI (oxidation)
C-II + e- → C-III (reduction)
K2MnO4 is an oxidizing agent, C2H5OH is a reducing agent, C2H5OH is an oxidizing agent.