Types of redox reaction
(a) Direct redox reaction: The reactions in which oxidation and reduction takes place in the same vessel are called direct redox reactions.
(b) Indirect redox reaction: The reactions in which oxidation and reduction takes place in different vessels are called indirect redox reactions. Indirect redox reactions are the basis of electro-chemical cells.
(c) Intermolecular redox reactions: In which one substance is oxidised while the other is reduced.