Question

Assertion: KCl crystals appear violet in colour.

Reason: The violet colour is due to electrons trapped in anion vacancies.

विकल्प

• If both Assertion and Reason are CORRECT and Reason is the CORRECT explanation of the Assertion.

• If both Assertion and Reason are CORRECT but Reason is not the CORRECT explanation of the Assertion.

• If Assertion is CORRECT but Reason is INCORRECT.

• If Assertion is INCORRECT but Reason is CORRECT.

Answer 1

If both Assertion and Reason are CORRECT and Reason is the CORRECT explanation of the Assertion.

Explanation:

When KCl is heated in potassium vapour, some Cl⁻ ions leave their lattice sites, creating anion vacancies. These vacancies trap electrons, forming F-centres. These trapped electrons absorb visible light, and the crystal appears violet. Hence, the Reason correctly explains why KCl crystals appear violet.