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प्रश्न
Why is FeO (s) not formed in stoichiometric composition?
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उत्तर
In the crystals of FeO, some of the Fe2+ cations are replaced by Fe3+ ions. Three Fe2+ ions are replaced by two Fe3+ ions to make up for the loss of positive charge. Eventually there would be less amount of metal as compared to stoichiometric proportion.
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संबंधित प्रश्न
Explain the following term with a suitable example:
Interstitials
Give reasons : In stoichiometric defects, NaCl exhibits Schottky defect and not Frenkel defect.
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?
Ionic solids containing large differences in sizes of ions show ____________.
Defect shown by non-ionic solids is ____________.
Defects in solids can be studied using
Point defect is also known as ____________.
Type of stoichiometric defect shown by AgBr is ____________.
Which is not correct about the Schottky defects?
Assertion: Due to Frenkel defect, there is no effect on the density of the crystalline solid.
Reason: In Frenkel defect, no cation or anion leaves the crystal.
Which of the following crystals does not exhibit Frenkel defect?
What is the effect of Frenkel defect on the density of ionic solids?
In a Schottky defect ____________.
Schottky defect is observed in crystals when ______.
Which of the following point defects are shown by AgBr(s) crystals?
- Schottky defect
- Frenkel defect
- Metal excess defect
- Metal deficiency 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.
The incorrect statement about the imperfections in solids is ______.
Which type of ‘defect’ has the presence of cations in the interstitial sites?
