Question

Assertion: Anion vacancies in alkali halides are produced by heating the alkali halide crystals with alkali metal vapour.
Reason: Electrons trapped in anion vacancies are referred to as F-centers.

• A. If both assertion and reason are true and the reason is the correct explanation of the assertion.
• B. If both assertion and reason are true but reason is not the correct explanation of the assertion.
• C. If assertion is true but reason is false.
• D. If the assertion and reason both are false.

Answer 1

The correct option is B If both assertion and reason are true but reason is not the correct explanation of the assertion.

On heating, the metal atoms deposit on the surface and finally they diffuse into the crystal and after ionization the alkali metal ion occupies cationic vacancy whereas electron occupies anionic vacancy.