Ncert Exercises & Solutions

Which of the following defects decreases the density?

(a) Interstitial defect

(b) Vacancy defect

(d) Schottky defect

The correct choice among the given is-

1. (a, b)

2. (b, c)

3. (c, d)

4. (b, d)

Hint: When lattice sites are vacant then the density decreases

When some of the lattice sites are vacant, the crystal is said to have a vacancy defect.

It is basically a vacancy defect in ionic solids. In order to maintain electrical neutrality, the number of missing cations and anions

are equal. The Schottky defect also decreases the density of the substance.

Vacancy and Schottky defects lead to a decrease in density. Both are types of stoichiometric defects. In the case of

Frenkel defect and interstitial defect, there is no change in the density of the substance.