Kohlrausch Law Class 12 – Solved Problems
Q1. The equivalent conductance of a strong electrolyte increases on dilution due to
- An increase in the number of ions and the ionic mobility of the solution
- Complete dilution of the electrolyte at standard dilution
- An increase in the ionic mobility of solution
- None of Above
Option (3) is Correct
Explanation:
Equivalent conductance of a strong electrolyte increases on dilution due to an increase in the ionic mobility of the solution.
Q2. Calculate the limiting molar conductivity of sodium sulphate(Na2SO4). If the limiting molar conductivity of Na+ is 50.1 S.cm2/mol and 1/2 SO42- is 80.0 S.cm2/mol.
Solution:
Given,
- λ∞Na+ = 50.1 S.cm2/mol
- 1/2 λ∞SO42− = 80.0 S.cm2/mol
According to Kohlrausch’s Law of Independent Migration
λ∞(Na2SO4) = 2λ∞Na+ + 2×(1/2λ∞SO42−)
λ∞(Na2SO4) = 2 (50.1)+2×80
=> λ∞(Na2SO4) = 260.2 S.cm2/mol
So, the limiting molar conductivity of sodium sulphate is 260.2 S.cm2/mol.
Q3. The molar conductance of a solution ____ with dilution while its specific conductance ___ with dilution.
- Decreases, Increases
- Increases, Decreases
- Decreases, Decreases
- Increases, Increases
Option (1) is Correct
Explanation:
Molar conductance of a solution increases with dilution while its specific conductance decreases with dilution.
Kohlrausch Law
Kohlrausch’s law, also known as the law of Independent migration of Ions, tells us that the total of the limiting molar conductance of cations and anions of an electrolyte is equal to the molar conductivity of that electrolyte. This law helps us study electrochemical cells and diluted liquids and is applicable in determining weak electrolytes’ molar conductivity.
In this article, we will learn the concepts of Kohlrausch law, its applications, etc. We have to study Kohlrausch Law in Class 12 for board exams.
Table of Content
- What is Kohlrausch’s Law?
- What is Molar Conductivity?
- Formula of Kohlrausch law
- Kohlrausch’s Law of Independent Migration
- Application of Kohlrausch’s Law
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