Question

Impurity defect is a type of point defect. It can occur __________

(a) in one way, as substitution impurity defect

(b) in one way, as interstitial impurity defect

(c) in two ways, as substitution impurity defect or as interstitial impurity defect

(d) in two ways, as vacant impurity defect or as interstitial impurity defect

The question was asked in semester exam.

My question is taken from Imperfections in Solids in division Solid State of Chemistry – Class 12

Answer 1

Correct option is (c) in two ways, as substitution impurity defect or as interstitial impurity defect

To explain: An impurity defect occurs when a regular ion is replaced by some other type of ion, e.g. Na^+ is replaced by K^+. If the replacement occurs in the place of the regular cation, it is called a substitution impurity defect. If the replacement occurs in an interstitial position, it is called an interstitial impurity defect.