KCl crystallises in the same type of lattice as does NaCl Given that `r_(Na^(+))//r_(Cl^(-))=0.55` and `r_(K^(+))//r_(Cl^(-))=0.74`, the ratio of the side of unit cell for KCl to that of NaCl is

Options

A. 1.123
B. 0.891
C. 1.414
D. 1.112

Answer

A

Explanation

`(r_(Na^(+)))/(r_(Cl^(-)))=0.55,(r_(K^(+)))/(r_(Cl^(-)))=0.74`
`(r_(Na^(+)))/(r_(Cl^(-)))+1=1.55" "...(1)`
`(r_(Na^(+)))/(r_(Cl^(-)))+1=1.74" "...(2)`
Dividing (2) by (1)
`(1.74)/(1.55)=(r_(K^(+))+r_(Cl^(-)))/(r_(Cl^(-)))xx(r_(Cl^(-)))/(r_(Na^(+))+r_(Cl^(-)))`
`(r_(K^(+))+r_(Cl^(-)))/(r_(Na^(+))+r_(Cl^(-)))=1.122`