What is the Difference Between Conductivity and Molar Conductivity?

The difference between conductivity and molar conductivity lies in the fact that conductivity measures the ability of an electrolyte to conduct electricity through a specific volume of the solution, while molar conductivity measures the conductivity of a solution containing 1 mole of electrolyte dissolved in it.

• Conductivity: This is the measure of an electrolyte's ability to conduct electricity through it. It is quantitative and depends on the ionic species in the electrolyte, such as cations and anions, which contribute to the conductivity.
• Molar Conductivity: This is the conductance of a solution containing 1 mole of the electrolyte dissolved in it. It is denoted as Λm and has the SI unit of Sm²/mol. Molar conductivity is useful because it helps in understanding the effect of concentration changes on the conductivity of a solution.

For both weak and strong electrolytes, conductivity decreases with a decrease in concentration, as the number of ions per unit volume carrying electricity decreases. On the other hand, molar conductivity increases with a decrease in concentration. This is because, as the concentration of the electrolyte decreases, the amount of ions per unit volume decreases, leading to a decrease in conductivity. However, when considering the conductivity of 1 mole of the electrolyte, the molar conductivity increases with decreasing concentration.

Comparative Table: Conductivity vs Molar Conductivity

The main difference between conductivity and molar conductivity lies in the units and concentration dependence. Here is a comparison table of the two properties:

In summary, conductivity is the ability of an electrolyte to conduct electricity, and its SI unit is S/m, while molar conductivity is the conductivity of an electrolyte solution containing 1 mole of the electrolyte, and its SI unit is S m²/mol. Conductivity decreases with decreasing concentration, whereas molar conductivity increases with decreasing concentration.