Reduction — বিজারণ
Reduction is the gain of electrons — in the classical sense, the loss of oxygen or the gain of hydrogen.
Definition
Reduction is the partner half of every redox reaction: the gain of electrons — remember RIG, reduction is gain. In the older oxygen-centred language, reduction means losing oxygen, as when copper(II) oxide heated in a stream of hydrogen shines out as pink-brown copper metal. The substance that hands over the electrons is the reducing agent, and it ends up oxidized itself. Winning metals from their ores is mostly reduction: in the blast furnace, carbon monoxide snatches oxygen from iron ore and frees the iron.
For example
Pass hydrogen over hot black copper oxide and it comes out as glowing pink copper: + → Cu + — the oxide loses oxygen, the hydrogen takes it.