The pyknometric density of sodium chloride crystal is `2.165xx10^(3)kg m^(-3)` while its `X` ray density is `2.178xx10^(3)kg m^(-3)` the fraction of unoccupied sites in `NaCl` crystal is

Options

A. `5.96 xx 10^(-3)`
B. `5.96`
C. `5.96 xx 10^(-2)`
D. `5.96 xx 10^(-1)`

Answer

A

Explanation

Difference `=2.178 xx 10^(3) - 2.165 xx 10^(3) = 0.013 xx 10^(3)`
Fraction unoccupied `=(0.013 xx 10^(3))/(2.178 xx 10^(3)) = 5.96 xx 10^(-3)`