This document discusses chemical reactions and equations. It defines oxidation as a gain of oxygen and reduction as a loss of oxygen during a reaction. It explains that corrosion occurs when the surface of a metal is attacked by air, moisture, or other substances, such as rusting of iron. It also discusses rancidity, which is the oxidation of fats and oils over time that changes their color, smell, and taste.

1. Physical science
class-X
Chemical reaction and equation
SWETA KUMARI
11808380
INTEGRATED BSC.BED. (4TH 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.
A)True
B)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. Quiz 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