The pyknometric density of sodium chloride crystal is
2.165 x 103 kg m -3 while its X – rays density is 2.178 x 103 kg m -3 . The fraction of unoccupied sites in sodium chloride crystal is
a. 5. 96 x 10-3
b. 5.96
c. 5.96 x 10-2
d. 5. 96 x 10 -1
Ans. a
Explanation : Difference = 2.178 x 103 – 2.165 x 103 = 0.013 x 10 3
Fraction unoccupied = 0.013 x 10 -3 / 2.178 x 103 = 5.96 x 10 -3
(10)