Schottky defects occurs mainly in electrovalent compounds where

a. Positive ions and negative ions are of different size

b. Positive ions and negative ions are of same size

c. Positive ions are small and negative ions are big

d. Positive ions are big and negative ions are small

Ans. b

Explanation : Schottky defect is caused if some of the lattice points are unoccupied. The points which are unoccupied are called vacancies or holes. The number of missing positive and negative ions is the same keeping the crystal neutral. Cations and anions are of similar size

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