Advertisements
Advertisements
Question
Give reasons : In stoichiometric defects, NaCl exhibits Schottky defect and not Frenkel defect.
Advertisements
Solution
Schottky defect is shown by the ionic solids having very small difference in their cationic and anionic radius whereas Frenkel defect is shown by ionic solids having large difference in their cationic and anionic radius. In this case the radius of both Na+ and Cl- have very small difference in their radius as a result of it NaCl will show schottky defect.
APPEARS IN
RELATED QUESTIONS
Examine the given defective crystal:
Answer the following questions :
(i) What type of stoichiometric defect is shown by the crystal?
(ii) How is the density of the crystal affected by this defect?
(iii) What type of ionic substances show such defect?
Point defect is also known as ____________.
Dislocation defect is also known as ____________.
The following diagram shows:
Assertion: No compound has both Schottky and Frenkel defects.
Reason: Both defects change the density of the solid.
Which of the following statements are not true?
(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) Frankel defect results in an increase in the density of the substance.
Frenkel defect is also known as:
(i) stoichiometric defect
(ii) dislocation defect
(iii) impurity defect
(iv) non-stoichiometric defect
Match the defects given in Column I with the statements in given Column II.
| Column I | Column II |
| (i) Simple vacancy defect | (a) shown by non-ionic solids and increases density of the solid. |
| (ii) Simple interstitial defect | (b) shown by ionic solids and decreases density of the solid. |
| (iii) Frenkel defect | (c) shown by non ionic solids and density of the solid decreases. |
| (iv) Schottky defect | (d) shown by ionic solids and density of the solid remains the same. |
Given below are two statements, one is labelled as Assertion (A) and the other is labelled as Reason (R):
Assertion: In any ionic solid (MX) with Schottky defects, the number of positive and negative ions are same.
Reason: Equal number of cation and anion vacancies are present.
If NaCl is doped with 10–4 mole percent of SrCl2 the concentration of cation vacancies will be
