Q60 / 180 · AIIMS 2008 · Chemistry
A unit cell of sodium chloride has four formula units. The edge length of the unit cell is \(0.564 \mathrm{~nm}\). What is the density of sodium chloride?
- A\(1.2 \mathrm{~g} / \mathrm{cm}^3\)
- Correct answerB\(2.165 \mathrm{~g} / \mathrm{cm}^3\)
- C\(3.64 \mathrm{~g} / \mathrm{cm}^3\)
- D\(4.56 \mathrm{~g} / \mathrm{cm}^3\)
Solution
$\begin{aligned} & \text { Density }=\frac{n M}{N_A \times a^3} \\ & =\frac{4 \times 58.5}{6.023 \times 10^{23} \times\left(5.64 \times 10^{-8}\right)^3}=2.17 \mathrm{~g} / \mathrm{cm}^3\end{aligned}$
begin{aligned} & \text { : Density }=\frac{n M}{N_A \times a^3} \\ & =\frac{4 \times 58.5}{6.023 \times 10^{23} \times\left(5.64 \times 10^{-8}\right)^3}=2.17 \mathrm{~g} / \mathrm{cm}^3\end{aligned}$
Hence, the correct answer is option: 'B'.