Solid State - Result Question 30
####30. Statement I In any ionic soid $(M X)$ with Schottky defects, the number of positive and negative ions are same.
Statement II Equal numbers of cation and anion vacancies are present.
$(2001,1 M)$
Passage Based Questions
Passage
In hexagonal systems of crystals, a frequently encountered arrangement of atoms is described as a hexagonal prism. Here, the top and bottom of the cell are regular hexagons and three atoms are sandwiched in between them. A space-filling model of this structure, called hexagonal close-packed (hcp), is constituted of a sphere on a flat surface surrounded in the same plane by six identical spheres as closely as possible. Three spheres are then placed over the first layer so that they touch each other and represent the second layer. Each one of these three spheres touches three spheres of the bottom layer.
Finally, the second layer is covered with a third layer that is identical to the bottom layer in relative position. Assume radius of every sphere to be ’ $r$ ‘.
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Answer:
Correct Answer: 30. (a)
Solution:
- In ionic solid $M X$ (1:1 solid) same number of $M^{n+}$ and $X^{n-}$ ions are lost in Schottky defect to maintain electroneutrality of solid.
