Q11 / 150 · MHT CET 2026 (15 April Shift 1) · Chemistry
Which of the following is NOT a characteristic of Schottky defect?
- AAfter defect stoichiometry, the crystal remains unchanged.
- BAfter defect neutrality, the crystal's structure remains unchanged.
- Correct answerCAfter defect density of crystal remains unchanged
- DIt is a vacancy defect.
Solution
Schottky defect is a type of point defect in a crystal lattice that occurs when an equal number of cations and anions are missing from their lattice sites.
Since equal numbers of oppositely charged ions are missing, the stoichiometry and electrical neutrality of the crystal are maintained.
Because it involves missing ions, it is a vacancy defect.
Due to the loss of ions from the crystal lattice, the mass of the crystal decreases while its volume remains the same. Therefore, the density of the crystal decreases.
Thus, the statement that the density of the crystal remains unchanged is incorrect.
Answer: After defect density of crystal remains unchanged
Since equal numbers of oppositely charged ions are missing, the stoichiometry and electrical neutrality of the crystal are maintained.
Because it involves missing ions, it is a vacancy defect.
Due to the loss of ions from the crystal lattice, the mass of the crystal decreases while its volume remains the same. Therefore, the density of the crystal decreases.
Thus, the statement that the density of the crystal remains unchanged is incorrect.
Answer: After defect density of crystal remains unchanged
Hence, the correct answer is option: 'C'.