Explain the following in terms of gain or loss of oxygen with two examples each.
(a) Oxidation
(b) Reduction

Explanation

(a) Oxidation: It is defined as a process which involves gain of oxygen. For example,
(i) `underset("Megnesium")(2Mg(s))+underset("Oxygen")(O_(2)(g))rarrunderset("Magnesium oxide")(2MgO(s))`
Here, Mg has gained oxygen to form MgO. Hence, Mg has been oxidised to MgO.
(ii) `underset("Copper")(2Cu(s))+underset("Oxygen")(O_(2)(g))overset("Heat")rarrunderset("Copper oxide")(2CuO(s))`
In this reaction, Cu has gained oxygen to form CuO. Thus, Cu is oxidised to copper oxide (CuO).
(b) Reduction: It is defined as the process which involves loss of oxygen. For example,
(i) `underset("Copper oxide")(CuO)+underset("Hydrogen")(H_(2))overset("Heat")rarrunderset("Copper")(Cu)+underset("Water")(H_(2)O)`
In this reaction, copper oxide is losing oxygen. So, it is being reduced to copper.
(ii) `underset("Zinc oxide")(ZnO)+underset("Carbon")(C)overset("Heat")rarrunderset("Zinc")(Zn)+underset("Carbon monoxide")(CO)`
In this reaction, zinc oxide is losing oxygen. So it is being reduced to zinc.