MHT CET Medical202624 April 2026Morning ShiftChemistrySolid StateActual
The volume of fcc unit cell is 5.6 10⁻²³ cm ^3 . Calculate the molar mass of metal if the density of metal is 20.4 g cm ⁻³ . [ N_A=6.022 10²³ ]
Options
- A172 g mol ⁻¹
- B192 g mol ⁻¹
- C156 g mol ⁻¹
- D180 g mol ⁻¹
Correct answer
A. 172 g mol ⁻¹
Step-by-step solution
The density of a unit cell is given by the formula: d = Z M N_A V For an fcc unit cell, the number of atoms per unit cell is Z = 4 . Rearranging the formula to solve for molar mass M : M = d N_A V Z Substituting the given values: M = 20.4 6.022 10²³ 5.6 10⁻²³ 4 M = 20.4 6.022 5.6 4 M = 171.98 172 g mol ⁻¹ Answer: 172 g mol ⁻¹