Redox and Electrolysis (Chemistry)

Oxidation and reduction in terms of oxygen transfer

Definitions:

Oxidation is gain of oxygen

Reduction is loss of oxygen

Redox is a contraction of the name for chemical reduction-oxidation reaction. A reduction reaction always occurs with an oxidation reaction. Redox reactions include all chemical reactions in which atoms have their oxidation state changed; in general, redox reactions involve the transfer of electrons between chemical species. The chemical species from which the electron is stripped is said to have been oxidized, while the chemical species to which the electron is added is said to have been reduced. Oxygen is not necessarily included in such reactions as other chemical species can serve the same function.

Electrolysis is the process by which ionic substances are decomposed (broken down) into simpler substances when an electric current is passed through them. For electrolysis to work, the ions must be free to move. Ions are free to move when an ionic substance is dissolved in water or when melted.

Here is what happens during electrolysis:

- Positively charged ions move to the negative electrode during electrolysis. They receive electrons and are reduced.

- Negatively charged ions move to the positive electrode during electrolysis. They lose electrons and are oxidized.

The substance that is broken down is called the electrolyte.