electrons are shown as e-the numbers of atoms of each element must be the same on both sides the total charge on each side must be the same (usually zero) For the half equation: Al 3+ + 3e-→ Al ...

The volume of hydrogen given off is twice the volume of oxygen given off.

Redox reactions, EMF of a cell, standard electrode potential, Nernst equation and its application ... Kohlrausch's Law, electrolysis and law of electrolysis (elementary idea), dry cell ...