NTA Abhyas JEE Main2020ChemistrySolid StatePractice
The radii of N a + and C l - ions are 95 pm and 181 pm respectively. The edge length of N a C l unit cell is
Options
- A276 pm
- B138 pm
- C552 pm
- D415 pm
Correct answer
C. 552 pm
Step-by-step solution
N a C l has fcc structure. In fcc lattice with ions in octahedral voids r + + r − = a 2 Where, a   = edge length r + = 95 pm, r − = 181 pm Edge length = 2r + + 2r − = ( 2 × 95 + 2 × 181 ) pm = 190 + 362 = 552 pm