Oxidation-reduction reaction, corrosion and rancidity

Oxidation is the gain of oxygen.
Reduction is the loss of oxygen.
When the surface of a metal is attacked by air, moisture or any other substance around it, the metal is said to corrode and the phenomenon is known as corrosion.
The process of oxidation of fats and oils which can be noticed by a change in colour, smell, and taste is known as rancidity.”
Example: When butter is kept in the open atmosphere than its smell and taste change which results in rancidity.

1. Physical science class-X Chemical reaction and equation SWETA KUMARI 11808380 INTEGRATED BSC.BED. (4 TH YEAR) LOVELY PROFESSIONAL UNIVERSITY, PHAGWARA

2. Look at the picture carefully

3. Compare

4. Oxidation-reduction reaction If a substance gains oxygen during a reaction, it is said to be oxidized. If a substance loses oxygen during a reaction, it is said to be reduced . NOTE: Oxidation is the gain of oxygen. Reduction is the loss of oxygen.

5. Identify the images

6. Corrosion When the surface of a metal is attacked by air, moisture or any other substance around it, the metal is said to corrode and the phenomenon is known as corrosion. Example is rusting of iron. 4Fe + 3O2 + 6H2O → 4Fe(OH)3

7. True or False Q1. Parts of machines that move can be protected from corrosion by coating layers of water repellent oil or grease. True False

8. Have you ever tasted or smelt the fat/oil containing food materials left for a long time?

9. Rancidity The process of oxidation of fats and oils which can be noticed by a change in colour, smell, and taste is known as rancidity.” Example: When butter is kept in the open atmosphere than its smell and taste change which results in rancidity.

10. Q uiz Time Q1. A substance added to food containing fats and oils is called: (a) Oxidant (b) Rancid (c) Coolant (d) Antioxidant

11. Match the following i) Loss of oxygen ii) Gain of oxygen iii) The process in which metals are slowly eaten up by the action of air moisture or chemicals. iv) When the substance containing oils and fats are exposed to air they get oxidized and become rancid due to which their smell, taste and colour change. A) Rancidity B) Reduction C) Oxidation D) Corrosion