Question
Calculate the number of atoms present in 90 g of metal if it forms bcc structure. [ a^3 = 1.8 10^ -22 g ]
MHT CET
Chemistry
Solid State
2026
MHT CET 2026 (16 April Shift 1)
MHT CET Chemistry Question (2026) — Solution
Options
- A. 4.0 10^ 24
- B. 1.0 10^ 24
- C. 2.0 10^ 24
- D. 3.0 10^ 24
Answer
B. 1.0 10^ 24
Step-by-step solution
Mass of one unit cell is given by a^3 = 1.8 10^ -22 g. For a body-centered cubic (bcc) structure, the number of atoms per unit cell is Z = 2. Mass of 2 atoms = 1.8 10^ -22 g. Mass of 1 atom = 1.8 10^ -22 2 = 0.9 10^ -22 g. Number of atoms in 90 g of the metal = 90 0.9 10^ -22 = 100 10^ 22 = 1.0 10^ 24 . Answer: 1.0 10^ 24
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