Molar Conductivity: Full Explanation
1. Introduction to Molar Conductivity
Molar conductivity (Lambda_m) is the conductance of a solution containing one mole of electrolyte,
dissolved in a given volume such that the ions are free to move. It helps in understanding ion
behavior in solutions.
2. Formula and Unit of Molar Conductivity
Molar conductivity is given by: Lambda_m = (k x 1000) / C where k is the conductivity (S/m) and
C is the molar concentration (mol/m³). SI Unit: S·m²/mol
3. Variation of Molar Conductivity with Concentration
- Strong Electrolytes: Molar conductivity increases slightly with dilution due to reduced ion
interactions. - Weak Electrolytes: Molar conductivity increases significantly with dilution due to
greater ion dissociation.
4. Kohlrausch’s Law of Independent Migration of Ions
This law states that at infinite dilution, the molar conductivity of an electrolyte is the sum of
the individual contributions of its ions: Lambda_m0 = lambda_0+ + lambda_0- where lambda_0+ and
lambda_0- are the limiting molar conductivities of cations and anions.
5. Measurement of Molar Conductivity
- Conductivity Cell: A device with electrodes used to measure conductivity. - Procedure:
Conductivity is measured at different concentrations, and molar conductivity is calculated.
6. Applications of Molar Conductivity
- Electrochemistry: Helps in determining ion transport numbers. - Industrial Use: Used in designing
batteries and fuel cells. - Laboratory Analysis: Helps in determining dissociation constants of weak
electrolytes.
7. Conclusion
Molar conductivity is a crucial concept in electrochemistry, helping to understand ionic behavior in
solutions. Its study is essential for applications in scientific research and industry.
1. Introduction to Molar Conductivity
Molar conductivity (Lambda_m) is the conductance of a solution containing one mole of electrolyte,
dissolved in a given volume such that the ions are free to move. It helps in understanding ion
behavior in solutions.
2. Formula and Unit of Molar Conductivity
Molar conductivity is given by: Lambda_m = (k x 1000) / C where k is the conductivity (S/m) and
C is the molar concentration (mol/m³). SI Unit: S·m²/mol
3. Variation of Molar Conductivity with Concentration
- Strong Electrolytes: Molar conductivity increases slightly with dilution due to reduced ion
interactions. - Weak Electrolytes: Molar conductivity increases significantly with dilution due to
greater ion dissociation.
4. Kohlrausch’s Law of Independent Migration of Ions
This law states that at infinite dilution, the molar conductivity of an electrolyte is the sum of
the individual contributions of its ions: Lambda_m0 = lambda_0+ + lambda_0- where lambda_0+ and
lambda_0- are the limiting molar conductivities of cations and anions.
5. Measurement of Molar Conductivity
- Conductivity Cell: A device with electrodes used to measure conductivity. - Procedure:
Conductivity is measured at different concentrations, and molar conductivity is calculated.
6. Applications of Molar Conductivity
- Electrochemistry: Helps in determining ion transport numbers. - Industrial Use: Used in designing
batteries and fuel cells. - Laboratory Analysis: Helps in determining dissociation constants of weak
electrolytes.
7. Conclusion
Molar conductivity is a crucial concept in electrochemistry, helping to understand ionic behavior in
solutions. Its study is essential for applications in scientific research and industry.
