3. Defn 1 (In terms of oxygen) Oxidation = addition/gain of oxygen A substance that gains oxygen is said to be oxidised. Reduction = removal/loss of oxygen. A substance that loses oxygen is said to be reduced.
4.
5. Example based on Defn 1 (In terms of oxygen) 2. Fe 2 O 3 + 3CO -> 2Fe + 3CO 2 Carbon monoxide (CO) is oxidised. Iron (III) oxide (Fe 2 O 3 ) is reduced.
6. Defn 2 (In terms of hydrogen) Oxidation = removal/loss of hydrogen A substance that loses hydrogen is said to be oxidised. Reduction = addition/gain of hydrogen. A substance that gains hydrogen is said to be reduced.