In orthorhombic unit cell the value of a, b and c are respectively 4.2 Å,8.6 Å and 8.3 Å . Given the molecular mass of the solute is 155 gmol^ - 1 and density is 3.3 g/cc , the number of formula units per unit cell is

Correct answer: C. 4 Z = V × N _ A × ρ M V = Volume of unit cell = a × b × c = 4.2 × 8.6 × 8.3 × 10 ^ - 24 × 6.023 × 10 ^ 23 × 3.3 155 = 3.84 ≃ 4

NTA Abhyas 2020

NTA Abhyas 2020 · Chemistry · Solid State

In orthorhombic unit cell the value of a, b and c are respectively...

In orthorhombic unit cell the value of

\text{a, b}

and

\text{c}

are respectively

\text{4}\text{.2 Å,}\text{8}\text{.6 Å}

and

\text{8}\text{.3 Å}

. Given the molecular mass of the solute is

\text{155 g}mol^{- 1}

and density is

\text{3}\text{.3 g/cc}

, the number of formula units per unit cell is (Report your answer by rounding up to nearest integer)

C. $\text{4}$

\text{Z} = \dfrac{\text{V} \times {N}_{A} \times \text{ρ}}{M}

V = Volume of unit cell =

\text{a} \times \text{b} \times \text{c}

= \dfrac{4.2 \times 8.6 \times 8.3 \times {10}^{- 24} \times 6.023 \times {10}^{23} \times 3.3}{155} = 3.84 ≃ 4