Incorrect(s) statement among the following:

I. Vacancy defect results in a decrease in the density of the substance.
II. Interstitial defects results in an increase in the density of the substance.
III. Impurity defect has no effect on the density of the substance.
IV. Frenkel defect results in an increase in the density of the substance.

1. (I, II)

2. (II, III)

3, (III, IV)

4. (I, IV)

HINT: There is no effect on density in Frenkel defect.

Explanation:
 Frenkel defect results neither decrease nor increase in density of substance.The defect forms when an atom or smaller ion leaves its place in the lattice, creating a vacancy and becomes an interstitial by lodging in a nearby location.