Question

The molar conductances at infinite dilution `(∧_0)` for electrolytes B⁺A⁻ and C⁺A⁻ are 140 and 120 S cm² mol⁻¹. The molar conductance at infinite dilution for B⁺X⁻ is 198 S cm² mol⁻¹. The `∧_0` (in S cm² mol⁻¹) of C⁺X⁻ is __________.

Options

• 178

• 198

• 218

• 130

Answer 1

The molar conductances at infinite dilution `(∧_0)` for electrolytes B⁺A⁻ and C⁺A⁻ are 140 and 120 S cm² mol⁻¹. The molar conductance at infinite dilution for B⁺X⁻ is 198 S cm² mol⁻¹. The `∧_0` (in S cm² mol⁻¹) of C⁺X⁻ is 178.

Explanation:

`∧_0 ("BA") = λ_("B"^+)^0 + λ_("A"^-)^0`

`∧_0 ("CA") = λ_("C"^+)^0 + λ_("A"^-)^0`

`∧_0 ("BX") = λ_("B"^+)^0 + λ_("X"^-)^0`

∴ `∧_0 ("CX") = ∧_0 ("CA") + ∧_0 ("BX") - ∧_0 ("BA")`

= 120 + 198 − 140

= 178 S cm² mol⁻¹