Most Important Selected Qs for JEE AdvancedChemistrySolid State
Paragraph: A solid crystal is composed of X, Y and Z atoms, Z atoms (radius 200 pm ) form cubic close packed structure, whereas X (radius 50 pm ) and Y (radius 100 pm ) occupy respective voids - Assume all the voids are occupied. Now answer the following questions. Question: If all the atoms along one body diagonal are removed, then the formula of the compound becomes :
Options
- AX ₈ Y ₄ Z ₅
- BX ₈ Y ₄ Z ₄
- CX ₆ Y ₃ Z ₃
- DX ₆ Y ₃ Z ₄
Correct answer
A. X ₈ Y ₄ Z ₅
Step-by-step solution
In the original compound Z atoms form CCP X atoms present in tetrahedral void. ( r X r Z = 50 200 =0.25 ) Y atoms present in octahedral void ( r Y r Z = 100 200 =0.5 ) Assuming, all voids are occupied, formula of the original compound =X₈ Y₄ Z₄ . On removing atoms along one body diagonal, We lose 2 Z atoms, 2 X atoms, 1 Y atom (body centre) The new formula becomes X ₆ Y ₃ Z _ 3.75 Simplest formula X ₈ Y ₄ Z ₅