The number of unit cells present in 39g of potassium if it crystallizes as body centred cube is (N = Avogadro number, At. wt. of potassium = 39)

Options

A. `N/4`
B. `N/2`
C. `y^(N)`
D. N

Answer

b

Explanation

Number of moles of potassium `= 39/39` = 1 mole
1 mole of potassium = `6.023 xx 10^(23)` atoms = N
In bcc, one unit cell contains two atoms.
i.e., 2 atoms – 1 unit cell
N atoms-- `(Nxx1)/2`