Which of the following statement(s) is/are correct?a)Vacancy defects r...
(c, d) Statements (c) and (d) can be correctly written as (c) Impurity defect changes the density of substance as impurity has different than the ion present on perfect crystal e.g., When SrCl2 is added to the NaCl crystal, it causes impurity defect, (d) Frenkel defect results neither decrease nor increase in density of substance.
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Which of the following statement(s) is/are correct?a)Vacancy defects r...
Introduction:
Vacancy, interstitial, impurity, and Frenkel defects are all types of point defects that can occur in a crystal lattice. These defects can affect the density of the substance in different ways. Let's analyze each statement to determine which one(s) are correct.
A) Vacancy defects result in the decrease in the density of the substance:
- A vacancy defect occurs when an atom is missing from its lattice site. This creates an empty space or a "vacancy" in the crystal lattice.
- Since there is less mass occupying the lattice sites, the overall density of the substance decreases.
- Therefore, statement A is correct.
B) Interstitial defects result in the increase in the density of the substance:
- An interstitial defect occurs when an atom occupies an interstitial site, which is an empty space between lattice points.
- This introduces additional mass into the crystal lattice, leading to an increase in the overall density of the substance.
- Therefore, statement B is correct.
C) Impurity defect has no effect on the density of the substance:
- An impurity defect occurs when foreign atoms or ions are present in the crystal lattice.
- The presence of impurities does not directly affect the mass or density of the substance. However, impurity atoms can introduce additional lattice distortion, which may indirectly affect the density.
- Therefore, statement C is incorrect.
D) Frenkel defect results in an increase in the density of the substance:
- A Frenkel defect occurs when an atom is displaced from its lattice site and occupies an interstitial site.
- This defect does not change the overall mass of the substance since the displaced atom still remains in the lattice.
- Therefore, statement D is incorrect.
Conclusion:
Based on the analysis above, both statement A and B are correct. Vacancy defects lead to a decrease in density, while interstitial defects result in an increase in density. Statement C is incorrect as impurity defects can indirectly affect the density, and statement D is incorrect as Frenkel defects do not change the overall mass of the substance.