Dispersion forces are the intermolecular forces of attraction present in all types of molecules. These are the weakest forces of attraction in which atoms of the molecule align in such a way that weak forces of attraction develop between electron cloud of one atom and the positively charged nucleus of the adjacent atom. This is referred to as induced dipole-induced dipole type of interaction. Therefore in dispersion forces temporary dipoles are developed due to constant motion of electrons that results in asymmetric electron distribution around the nucleus in an atom.
The correct subscript for the reaction would be two. Oxygen gas exists as a diatomic molecule in nature. Also, the subscript two would balance the reaction. In balancing reactions, it is important that the atoms on each side of the reaction is equal.
