Question

Which among the following is a slow, irreversible and chemical change?

• A. Fermentation
• B. Cooking
• C. Melting of butter
• D. Formation of clouds

Answer 1

The correct option is A

Fermentation

Explanation for the correct option:

Option A

• Fermentation is a slow, desirable, irreversible, and chemical change.
• To ferment any substance it will take time for many hours, the changes which take time to have happened are called slow changes.
• During the fermentation alcohol and carbon dioxide are formed. So new substance is formed, and it is a characteristic of chemical change.

Therefore, option A is correct.

Explanation for the incorrect option:

Option B

Cooking is man-made, desirable, irreversible, chemical, and fast change.

Therefore, option B is incorrect.

Option C

Melting of butter is a fast, desirable, reversible, man-made, and physical change.

Therefore, option C is incorrect.

Option D

• Formation of clouds is a physical change.
• Formation of clouds occurs due to the phase transformation of water from liquid to gas during the water cycle.
• In this process only the physical state changes.

Therefore, option D is incorrect.