(a) State the law which helps to determine the limiting molar conductivity of weak electrolytes.
(b) Calculate limiting molar conductivity of `CaSO^4` (limiting molar conductivity of calcium and sulphate ions are 119.0 and 106.0 S `cm^2 mol^(-1)` respectively).

Explanation

(a) The law which helps to determine the limiting molar conductivity of weak electrolytes is Kohlaursch Law. It states :
The limiting molar conductivity of an electrolyte can be represented as the sum of the individual contribution of the anion and the cation of the electrolyte.
(b) Limiting molar conducitivity of `CaSO_(4)` can be determined as under:
`Lambda_(m)^(@) CaSO_(4) = lambda_(Ca^(2+))^(@) + lambda_(SO_(4)^(2-))^(@) = 119.0 S cm^(2) mol^(-1) + 106.0 S cm^(2) mol^(-1) = 225.0 S cm^(2) mol^(-1)`.