n class 12 chemistry, conductivity and molar conductivity are both measures of the ability of a substance to conduct electricity, but they differ in terms of the quantities they describe and the units of measurement used. Here’s a breakdown of the differences between conductivity and molar conductivity:

1. Definition:
   • Conductivity: Conductivity refers to the ability of a substance or solution to conduct electric current. It is a general term that can be applied to any conducting material or solution.
   • Molar Conductivity: Molar conductivity specifically refers to the conductivity of an electrolyte solution at a particular concentration, measured between two electrodes. It is a property that describes the behavior of ions in solution.
2. Quantities Described:
   • Conductivity: Conductivity provides a measure of how well a material or solution conducts electric current. It is a bulk property that describes the overall ability of the substance to allow the flow of electrons.
   • Molar Conductivity: Molar conductivity describes the conductivity of an electrolyte solution in terms of the contribution of individual ions present in the solution. It provides insights into the extent of ion dissociation or ionization in the solution.
3. Units of Measurement:
   • Conductivity: Conductivity is typically measured in siemens per meter (S m⁻¹) or mho per meter (Ω⁻¹ m⁻¹).
   • Molar Conductivity: Molar conductivity is measured in siemens per meter squared per mole (S m² mol⁻¹) or mho meter squared per mole (Ω⁻¹ m² mol⁻¹).
4. Concentration Dependency:
   • Conductivity: Conductivity may or may not depend on the concentration of the substance or solution being measured.
   • Molar Conductivity: Molar conductivity is explicitly dependent on the concentration of the electrolyte solution. It changes with varying concentrations, reflecting the influence of the concentration on the mobility and availability of ions in the solution.

In summary, conductivity is a general term that describes the ability of a substance to conduct electricity, while molar conductivity specifically refers to the conductivity of an electrolyte solution at a particular concentration and focuses on the behavior of ions in solution. Molar conductivity is concentration-dependent and provides information about the extent of ion dissociation or ionization in the solution.