Question

The limiting molar conductivities `Lambda^@` for `NaCL, KBr` and `KCI` are ` 126, 152` and `150 S cm^2 ,ol^(-1)` respectively . The `Lambda^@` fro `NaBr S cm^2 "mol"^(-1)` is :
A. `288`
B. `302`
C. `156`
D. `128`

Answer 1

Correct Answer - D
`overset(@)(Lambda)_(NaCl) = overset(@)(Lambda)_(Na^(+)) + overset(@)(Lambda)_(Cl^(-))` ….(1)
`overset(@)(Lambda)_(KBr) = overset(@)(Lambda)_(K^(+)) + overset(@)(Lambda)_(Br^(-))` ….(2)
`overset(@)(Lambda)_(KCl) = overset(@)(Lambda)_(K^(+)) + overset(@)(Lambda)_(Cl^(-))`....(3) Eq. `(1) + (2) - (3)`
`overset(@)(Lambda)_(NaBr) = overset(@)(Lambda)_(Na^(+)) + overset(@)(Lambda)_(Br^(-))`
`= (126 + 152) - 150 = 128 S cm^(2) mol^(-1)`