Molar Conductivity Numericals
Problems 1: At 298 K, conductivity of 0.02 M solution of KCl is found out to be equal to 0.146 S cm^-1 Calculate the molar conductivity.
Solution :
Molarity (M) = 0.20M
Specific Conductance at 298 K is (k) = 0.0248 S.cm
Molar Conductivity = (100 × K) /M
= (100 × 2.48 ) / 2
= 124 cm² mol⁻¹
Thus, KCl solution has a molar conductivity of 124cm²mol⁻¹.
Problem 2: At infinity dilution, critical values of conductance for Na+ and Cl– are: 51.12 × 10-4 Sm2mol-1 and 73.54 × 10-4 Sm2mol-1. Determine the overall molar conductance of NaCl.
Solution:
Molar conductance at infinite dilution
λ(Na+) = 51.121 × 10-4 Sm2mol-1
λ(Cl–) = 73.54 × 10-4 Sm2mol-1
In terms of molar conductance, NaCl = λ(Na+) + λ(Cl–)
= 51.12 × 10-4 + 73.54 × 10-4
= 124.66 × 10-4 Sm2mol-1
Hence, the molar conductivity of NaCl is 124.66 × 10-4 Sm2 mol–².
Problem 3: The values of Molar conductances at infinite dilutions for Na + and Cl – ions are 32.54×10-2 Sm2.mol-1 and 67.12 × 10-2Sm2.mol-1. What is the complete Molar conductance of NaCl?
Solution :
Molar conductance at infinite dilution is calculated as follows:
λ(Na+) = 32.54 ×1 0-2Sm2.mol-1
λ(Cl–) = 67.12 mM2 mol-1
Molar Conductance of NaCl = λ(Na+) + λ(Cl–) = 32.54 × 10-2 +67.12 × 10-2
= 99.66 ×10-2 Sm2mol-1
As such, NaCl molar conductance equals 99.66 × 10-2Sm2mol-1.
Problem 4: Calculate the molar conductivity (Λom) for CaCl2, given:
Λ Ca2+ = 119.0 S.cm2mol-1
Λ Cl– = 76.3 S.cm2mol-1
Solution:
Λom(CaCl2) = ΛCa2+ + 2×ΛCl–
(Since CaCl2 consists of one calcium and two chloride ions, so we add their molar conductivity to get the same of the compound)
Λom(CaCl2) = 119.0 + 2×(76.3)
(Substituting the values of molar conductivity of the respective ions)
Λom(CaCl2) = 271.6 S.cm2mol-1.
Molar Conductivity
Molar Conductivity is a basic physical chemistry concept that greatly impacts the understanding of electrical conduction in electrolyte solutions. This parameter denoted by the symbol Λm sheds light on this ion’s ability to transport current in solution. With the concentration of ions and their mobility, molar conductivity is a criterion for clarifying electrolyte behavior. Molar conductivity is important topic in class 12 Electrochemistry.
In this article, we will learn about Molar Conductivity, Formula for Molar Conductivity, Molar Conductance, and others in detail.
Table of Content
- What Is Molar Conductivity?
- Molar Conductance
- Limiting Molar Conductivity
- Importance of Molar Conductivity
- Applications of Molar Conductivity
- Specific Conductivity
- Electrolytic Conduction
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