Which is the incorrect statement?

Options

A $\text{F}{\text{e}}_{0.98}\text{O}$ has non-stoichiometric metal deficiency defect.
BDensity decreases in case of crystals with Schottky's defect.
C\text{N}\text{a}\text{C}\text{l} $\left(\text{s}\right)$ is insulator, silicon is semiconductor, silver is conductor, quartz is piezo electric crystal.
DFrenkel defect is favoured in those ionic compounds in which sizes of cation and anions are almost equal.

Correct answer

D. Frenkel defect is favoured in those ionic compounds in which sizes of cation and anions are almost equal.

Step-by-step solution

In Schottky defect atoms/points are totally missing from the lattice, the net density of crystal will get decreased.

In ${\text{Fe}}_{0.98}\text{O}$ the number of the cation is more than the number of missing anion, hence, it is non-stoichiometric metal deficiency defect.

Frenkel defect occurs only when cations are smaller when compared to the anions.

Note: Option A is changed from the exam to make it academically correct.

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