Name: Chemical Reactions and Their Characteristics
Uploaded: 2019-07-19
Duration: 3 min 32 s
Description: Have you seen that a piece of iron left outside begins to rust in some time? This is a chemical reaction taking place. Watch the video to learn about chemical reactions.

Question

Classify the following changes as desirable changes or undesirable changes:

S.No	Example	Desirable/Undesirable Change	Reason
1.	Occurrence of rain	_____	_____
2.	Cutting trees in the forest	_____	_____
3.	Changing the course of rivers to build dams	_____	_____
4.	Formation of manure from cow-dung	_____	_____
5.	Contamination of food	_____	_____
6.	Increase in the population of fishes	_____	_____
7.	Release of smoke from industries	_____	_____

Accepted Answer

Those changes that are useful for humans and are wanted are called as desirable changes whereas the changes that are destructive, painful and are not wanted are called undesirable changes.

S.No Example Desirable/Undesirable Change Reason

1. Occurrence of rain Desirable Change Rain is required for crops and also to increase groundwater level.

2. Cutting trees in the forest Undesirable Change Trees provide us oxygen and deforestation increases global warming.

3. Changing the course of rivers to build dams Desirable Change Dams are built for storing and conserving water as well as aquatic life.

4. Formation of manure from cow-dung Desirable Change Manure is added to crops and plants for their proper growth.

5. Contamination of food Undesirable Change The spoiled food cannot be eaten.

6. Increase in the population of fishes Desirable Change Fishes are a great source of proteins.

7. Release of smoke from industries Undesirable Change Smoke causes global warming as well as pollutes the environment.

Chhattisgarh Board Solutions for Chapter: Changes around Us, Exercise 4: Exercise 4

Chhattisgarh Board Science Solutions for Exercise - Chhattisgarh Board Solutions for Chapter: Changes around Us, Exercise 4: Exercise 4

Questions from Chhattisgarh Board Solutions for Chapter: Changes around Us, Exercise 4: Exercise 4 with Hints & Solutions

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