The volume of simple unit cell is $x \times 10^{-23} \mathrm{~cm}^3$. Calculate the value of $x$ if volume occupied by a particle in it is $2.1 \times 10^{-23} \mathrm{~cm}^3$.

In ionic solid, anions are arranged in ccp array and cations occupy $1 / 3$ tetrahedral voids. What is the formula of ionic compound?

[Consider $\mathrm{A}=$ cation; $\mathrm{B}=$ anion]

Which of the following statements is NOT correct regarding voids in lattice structure?

What is the total number of tetrahedral voids in 0.6 mole of compound that forms hcp structure?