Consider the half reaction, MnO4-→OH-MnO2, Number of water molecules involved in the balanced half reaction is/are
1
2
3
4
MnO4-→MnO2+2H2O ; MnO4-+4H2O→MnO2+2H2O+4OH- ; MnO4-+2H2O+3e-→MnO2+4OH- ;