Reduction

Reduction is a part of acid-base chemistry (movement of protons or hydronium ions), even more specifically, redox chemistry which is the transfer of electrons between compounds. When a molecule is reduced in a compound it means that molecule has gained an electron. Reduction is the gain of electrons or a decrease in oxidation state by a molecule, atom, or ion often through the electrolysis of water is the decomposition of water (H 2 O) into oxygen (O 2 ) and hydrogen gas (H 2 ) due to an electric current being passed through the water. Since in a complete chemical reaction, the number of electrons gained has to be equal the number of electrons lost, then reduction is always accompanied with oxidation.

An example of a redox reaction is the production of rust: