Question

Assertion: In any ionic solid $\left[MX\right]$ with schottky defects, the numbers of positive and negative ions are same.
Reason: Equal number of cation and anion vacancies are present.

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

Answer 1

Answer: (A)

Both assertion and reason are true and reason is the correct explanation of assertion.

Schottky Defect: This defect occurs when oppositely charged ions leave their lattice site creating vacancies in such a way that electrical neutrality of crystal is maintained. It is generally seen in highly ionic compounds where a difference in size of cation and anion is small.

So, an equal number of cations and anions vacancies are present in the crystals with Schottky Defect.