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. `5.96xx10^(-1)`
B. `5.96xx10^(-3)`
C. `5.96`
D. `5.96xx10^(-2)`

Answer

B

Explanation

The fraction unoccupied site in sodium chloride crystal ltBrgt `=("X-ray density - pyknometric density")/("X-ray density")`
`=(2.178xx10^(3)-2.165xx10^(3))/(2.178xx10^(3))=(0.013xx10^(3))/(2.178xx10^(3))`
`=(13)/(2178)=5.96xx10^(-3)`