Question

The removal of oxygen from a substance is called:
(A) Oxidation
(B) Corrosion
(C) Reduction
(D) Rancidity

Answer 1

Hint: Oxidation, reduction, corrosion and rancidity are all the different types of reaction taking place in nature. Oxidation and reduction are oppositely based and are interrelated to each other. Whereas, corrosion is based on non-living things and rancidity is based on the reactions taking place on food items; mostly.

Complete answer:
Let us focus on the basic definitions of the terms given and hence, decide the answer;
Oxidation-
The addition of oxygen to any substance is known as oxidation. Also, the removal of hydrogen from any substance is known as oxidation.
This occurs when the oxidation number of an atom increases.
Reduction-
The removal of oxygen from any substance is known as reduction. Also, the addition of hydrogen to any substance is known as reduction.
This occurs when the oxidation number of an atom decreases.
For example:
$ZnO+C\to Zn+CO$
Here, as Zn is losing oxygen; it is being reduced. On the other hand, as C is gaining oxygen; it is being oxidised.
Corrosion-
It is a natural process which converts a metal into its oxide form; stable form but resulting in the degradation of the refined form.
Rancidity-
This is the process of complete or incomplete oxidation of the food items when exposed to light or moisture; making it unsuitable for consumption.
In short, both corrosion and rancidity are the degradation reactions taking place in nature which is responsible for the many day to day life problems on the primary level.

Therefore, option (C) is correct.

Note:
Do note that the oxygen need not be present in the reaction for it to be called a redox reaction; but oxidation and reduction together are called a redox reaction.
Also, deoxygenation is a chemical reaction which involves the removal of oxygen atoms from a molecule; in general.