NTA Abhyas JEE Main2020ChemistrySolid StatePractice
Element X crystallizes in 12 co-ordination fcc lattice. On applying high temperature it changes to 8 co-ordination bcc lattice. Find the ratio of the density of the crystal lattice before and and after applying high temperature
Options
- A1:1
- B3:2
- C2 : 3
- D2 2 3 : 3 3
Correct answer
D. 2 2 3 : 3 3
Step-by-step solution
Co. number is 12 means it is fcc lattice Co. number is 8 means it is bcc lattice fcc bcc ρ 1 = 4 × a t . m a s s N a × a 1 3 ρ 2 = 2 × a t . m a s s N a × a 2 3 ρ 1 ρ 2 = 4 2 × a 2 3 a 1 3 = 2 × 4 r 3 3 ( 2 2 r ) 3 = 2 × 4 × 4 × 4 2 × 2 × 2 × 2 × 2 ( 3 3 ) = 4 2 3 3 = 2 ( 2 ) 3 ( 3 ) 3