"Oxidation reaction (i):"
Fe^(2+) rarr Fe^(3+) + e^-
"Reduction reaction (ii):"
MnO_4^(-) + 8H^(+) + 5e^(-) rarr Mn^(2+) + 4H_2O(l)
For both (i) and (ii), "charge is balanced" and "mass is balanced", as indeed they must be if we purport to represent chemical reality. The final redox reaction adds 5xx(i)+(ii) so that electrons, conceptual particles, do not appear in the final redox equation:
MnO_4^(-) + 5Fe^(2+) +8H^(+)rarr Mn^(2+) + 5Fe^(3+) +4H_2O(l)
Which is balanced (is it?) with respect to mass and charge. The reaction has a built in indicator in that MnO_4^- in intensely purple, whereas the reduction product Mn^(2+) is almost colourless. An endpoint could be vizualized.
