Permanganate ion is MnO4− (i) Conversion of permanganate into manganese (II) salt. MnO4−⟶Mn2+ x+(−2)4=−1+2 x+7 Change in number of electrons =7−2=5 (ii) Conversion of permanganate into manganate MnO4−⟶MnO42− x+(−2)4=−1x+(−2)4=−2   x=+7      x=+6 Change in number of electron =7−6=1 (iii) Conversion of permanganate into manganese dioxide (MnO2) MnO4−⟶Mn2+O2 x+(−2)4=−1  x+(−2)2=0    x=+7   x−4=0          x=+4 Change in number of electrons =7−4=3 Thus, the number of electrons involved in the given reduction processes are respectively 5,1,3