Question

Which of the following is a desirable change?

• A. Rusting of iron
• B. Soil erosion
• C. Pasteurization of milk
• D. Rotting of fruits

Answer 1

The correct option is C

Pasteurization of milk

The explanation for the correct option:

Option C

• Desirable change: The changes that are useful to human beings are said to be desirable changes.
• For example, the ripening of fruits, cooking of food, formation of curd from milk, pasteurization of milk, etc.

The explanation for the incorrect option:

Option A

• Chemical change: Chemical change is a permanent change in which the original substance loses its own composition and properties.
• During this change, one or more new substances are formed.
• Rusting of iron is a chemical change.
• When a piece of iron is left out in moist air, it slowly changes into a dull brittle brown substance called rust.
• The composition and properties of rust are different from those of iron.

Option B

• Undesirable change: A change that is harmful to human beings or causes destruction is called an undesirable change.
• For example, soil erosion, cyclonic storms, and rotting of fruits. etc.

Therefore, option C is correct.