JEE Main levelSingle correct optionDifficulty 2 of 3ss189
Assertion (A): Frenkel defects do not change the density of an ionic crystal.
Reason (R): In a Frenkel defect an ion is only displaced to an interstitial site, so the number of ions and the volume stay the same.
Choose the correct option.
ABoth A and R are true and R is the correct explanation of A
BBoth A and R are true but R is not the correct explanation of A
CA is true but R is false
DA is false but R is true
Answer: A
In a Frenkel defect the ion leaves its lattice site and occupies an interstitial site, so no ion leaves the crystal. Mass and volume are unchanged and so is the density; R correctly explains A.