Given the ionic conductance of `underset(underset(COO^(c-))(|))(COO^(c-)),K^(o+), ` and `Na^(o+)` are `74,50,` and `73cm^(2)ohm^(-1)eq^(-1)`, respectviley. The equivalent conductance at infinite dilution of the salt `underset(underset(COOK)(|))(COONa)` is

Options

A. `197 cm^(2) ohm^(-1) eq^(-1)`
B. `172 cm^(2) ohm^(-1) eq^(-1)`
C. `135.5 cm^(2) ohm^(-1) eq^(-1)`
D. `160.5 cm^(2) ohm^(-1) eq^(-1)`

Answer

C

Explanation

Total charge = 2
Number of equivalent of ion = `("Charge of the ion")/("Total charge")`
`therefore` Eq of `({:(COO^(-)) ,(|) ,(COO^(-)):}) = (2)/(2) = 1`
Eq of `Na^(+) = (1)/(2)` . Eq of `K^(+) = (1)/(2)`
`therefore lambda_(eq)^(@) ({:(COONa) ,(|) ,(COOK):})`
= `lambda_(eq)^(@) ({:(COO^(-)) ,(|) ,(COO^(-)):}) + (1)/(2) lambda^(@) Na^(+) + (1)/(2) lambda^(@) K^(+)`
`= 74 + (50)/(2) + (73)/(2) = 135.5 ohm^(-1) cm^(2) eq^(-1)`