Imperfection in Solids

Given below are two statements: one is labelled as Assertion $\left(\mathrm{A}\right)$ and the other is labelled as Reason $\left(\mathrm{R}\right)$.
Assertion $\left(\mathrm{A}\right)$: In a particular point defect, an ionic solid is electrically neutral, even if few of its cations are missing from its unit cells.
Reason $\left(\mathrm{R}\right)$: In an ionic solid, Frenkel defect arises due to dislocation of cation from its lattice site to interstitial site, maintaining overall electrical neutrality.

In the light of the above statements, choose the most appropriate answer from the options given below:

Which of the following statements regarding Frenkel defects is FALSE?

In a sample of naturally occurring iron oxide, every $30$ out of $200{\mathrm{Fe}}^{2+}$ ions are missing. The loss of positive charge is made up by adding required number of ${\mathrm{Fe}}^{3+}$ ions so as to restore electrical neutrality. The net formula for this sample is

If molten $\mathrm{AgCl}$ is crystallized with a small amount of ${\mathrm{CdCl}}_2$, some defects are observed in the resulting crystal. Which of the following statements is CORRECT?

Which of the following is incorrect about the given stoichiometric defects?

Copper crystallizes in a face centred cubic unit cell with a =0.556 nm. Calculate the density if it contains:

(i) 0.1% Frenkel defect

(ii) 0.1% Schottky defect

Select the incorrect statement about Schottky defect from the following.

In a solid lattice, the cation has left a lattice site and is located at an interstitial position The lattice defect is

Schottky defect in crystals is observed when

Match the following:

No crystal is found to be prefect at room temperature. The defects present in the crystals can be stoichiometric or non-stoichiometric. Due to nonstoichiometric defects, the formula of the ionic compound is different from the ideal formula. For example, the ideal formula of ferrous oxide should be $\mathrm{FeO}$ but actually in one sample, it was found to be ${\mathrm{Fe}}_{0.93}\mathrm{O}$. This is because the crystal may have some ferric ions in place of ferrous ions. These defects change the properties of the crystals. In some cases, defects are introduced to have crystals of desired properties as required in the field of electronics. Doping of elements of Group 14 with those of Group 13 or 15 is most common. In ionic compounds, usually impurities are introduced in which the cation has higher valency than the cation of the parent crystal, e.g., ${\mathrm{SrCl}}_2$ into $\mathrm{NaCl}$.

Which one of the following defects does not affect the density of the crystal ?

No crystal is found to be prefect at room temperature. The defects present in the crystals can be stoichiometric or non-stoichiometric. Due to nonstoichiometric defects, the formula of the ionic compound is different from the ideal formula. For example, the ideal formula of ferrous oxide should be $\mathrm{FeO}$ but actually in one sample, it was found to be ${\mathrm{Fe}}_{0.93}\mathrm{O}$. This is because the crystal may have some ferric ions in place of ferrous ions. These defects change the properties of the crystals. In some cases, defects are introduced to have crystals of desired properties as required in the field of electronics. Doping of elements of Group 14 with those of Group 13 or 15 is most common. In ionic compounds, usually impurities are introduced in which the cation has higher valency than the cation of the parent crystal, e.g., ${\mathrm{SrCl}}_2$ into $\mathrm{NaCl}$.

$\mathrm{NaCl}$ was doped with ${10}^{-3 }\mathrm{mol} \% {\mathrm{SrCl}}_2$. The concentration of cation vacancies is

For $\mathrm{NaCl},$ the number of Schottky pairs per ${\mathrm{cm}}^3$ at room temperature are

Identify the incorrect statement regarding crystals having Frenkel defect:

Which one of the following has both Schottky and Frenkel defects?

Frenkel and Schottky defects are:

Frenkel and Schottky defects are:

At zero kelvin, most of the ionic crystals posses

The composition of a sample of Wustite is ${\mathrm{Fe}}_{0.93}{\mathrm{O}}_{1.00}$. The percentage of $\mathrm{Fe} \left(\mathrm{III}\right)$ ions present in the sample is about