Q. For a salt XY, which is a strong electrolyte, the plot of Λm versus √c has a slope of −90.0 S cm² mol⁻³ᐟ² L¹ᐟ² at 298 K. At 0.01 M concentration of XY, the value of Λm is 145.0 S cm² mol⁻¹. The limiting molar conductivity of Y⁻ ion (λ°Y⁻, in S cm² mol⁻¹) at 298 K will be (Given : λ°X⁺ = 74.0 S cm² mol⁻¹)
A) 76.0
B) 80.0
C) 100.0
D) 90.0
Explanation
[Solution from source] Kohlrausch: Λm = Λ°m − A√c. With √0.01 = 0.1, 145.0 = Λ°m − 9.0, so Λ°m = 154.0. Then λ°Y⁻ = 154.0 − 74.0 = 80.0 S cm² mol⁻¹. Answer (2).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.