TS EAMCET 9-Sep-2020 Shift 2 Solved Paper

∵ In sodium chloride crystal, the distance between Na+ and Cl− is Ypm.
∵NaCl has fec structure in which Na+ occupies all octahedral voids, while Cl− ions are present at all corners and edge centers.
If, edge length =a
The distance between Na+ and Cl−=Ypm (Given)
a=2(rCI−+rNa+)=2Ypm
Hence, edge length is 2Y pm and option (b) is the correct answer.