Explain the following in terms of gain or loss of oxygen with two examples each.
(a) Oxidation:
Oxidation is the gain of oxygen. This process occurs when a substance combines with oxygen to form an oxide.
Example 1:
2 H2 (g) + O2 (g) → 2 H2O (l)
In this equation, hydrogen (H2) is oxidized to form water (H2O) by gaining oxygen.
Example 2:
2 Cu (s) + O2 (g) → 2 CuO (s)
In this equation, copper (Cu) is oxidized to form copper oxide (CuO) by gaining oxygen.
(b) Reduction:
Reduction is the loss of oxygen. It occurs when a substance loses oxygen to form a simpler compound.
Example 1:
CO2 (g) + H2 (g) → CO (g) + H2O (g)
In this equation, carbon dioxide (CO2) is reduced to carbon monoxide (CO) by losing oxygen.
Example 2:
CuO (s) + H2 (g) → Cu (s) + H2O (g)
In this equation, copper oxide (CuO) is reduced to copper (Cu) by losing oxygen.