Most Important Selected Qs for JEE AdvancedChemistrySolid State
Paragraph: In a cubic unit cell, atoms (A) are present at all corners, (B) are present at alternate face centre and all edge centres. Atoms (C) are present at face centres left from (B) and one at each body diagonal at distance of 1 / 4^ th of body diagonal from corner. Question: An axis is passed from the given unit cell connecting opposite face centres and all atoms touching the axis are removed. The possible formu
Options
- AAB ₃ C ₆ or AB ₄ C ₅
- BA ₃ ~B ₆ C ₇ or A ₃ ~B ₆ C ₅
- CA ₄ ~B ₅ C ₈ or A ₄ ~B ₅ C ₇
- DAB ₂ C or ABC ₂
Correct answer
A. AB ₃ C ₆ or AB ₄ C ₅
Step-by-step solution
If axis passes through face centre where B lies, then Number of B atoms =4- ( 1 2 2 )=3 Formula = AB ₃ C ₆ If axis passes through face centres where C lies, then Number of C atoms =6- 1 2 2=5 Formula = AB ₄ C ₅