Question

Assertion: On heating iodine crystal, iodine vapours are formed.

Reason: Iodine easily undergoes sublimation.

Mark the correct choice.

• A. If ‘A’ and ‘R’ are true and ‘R’ is the correct reason for ‘A’.
• B. If ‘A’ and ‘R’ are true but ‘R’ is not the correct reason for ‘A’.
• C. If ‘A’ is correct and ‘R’ is wrong.
• D. If ‘A’ is wrong and ‘R’ is correct.

Answer 1

The correct option is A

If ‘A’ and ‘R’ are true and ‘R’ is the correct reason for ‘A’.

Explanation for Assertion statement

1. On heating, Iodine forms a purple vapour which turns back to grey iodine crystals when it cools.
2. There is no change as all the iodine turn back to solid iodine crystals.

Explanation for Reason statement

1. Iodine is a substance that is present in a crystalline form.
2. When this iodine is heated, it converts it into a gaseous form. The sublimation of iodine takes place in the presence of air or oxygen, the particles overcome the force of attraction between them and therefore sublimation takes place.

Therefore option (a) is the correct answer.