Question

3. Which of the following is a chemical change?

• A. the making of idlis
• B. grinding rice
• C. powdering of sugar crystals
• D. breaking of a window pane

Answer 1

The correct option is A

the making of idlis

Hint:

• Chemical changes are those in which new substances are formed.
• The properties of the new substances formed are very different from the original substances.
• Chemical changes are generally irreversible.

Explanation of correct option:

(A) The making of idlis:

• The making of idli is considered a chemical change because there is the formation of a new substance whose properties are different from the original substance.
• The making of idli is an irreversible change.
• Idli is made up of batter, but once it is prepared, it cannot be brought back to its original batter form.

(B) Grinding rice:

• It is a physical change because there is no formation of a new substance only the size of rice is reduced.

(C) Powdering of sugar crystals:

• It is a physical change because there is no formation of a new substance only the size of the sugar crystal is changed i.e. changed into fine particles.

(D) Breaking of a windowpane:

• It is a physical change because there is no formation of new substance only the size of the windowpane is reduced.

Conclusion: Hence, option (A) is correct.