Which term of molar conductivity is used when the concentration of electrolyte approaches to zero?

Limiting molar conductivity

The correct answer is Option (4) → Limiting molar conductivity.

When discussing the molar conductivity of electrolytes as their concentration approaches zero, the relevant term is limiting molar conductivity. Let's explore this concept in detail:

Explanation of Terms

1. Infinite Molar Conductivity:

This term is not commonly used in the context of electrolytes. It might imply conductivity at an infinitely high concentration, which is not a standard concept in electrochemistry.

2. Zero Molar Conductivity:

This term is not standard in electrochemistry. Conductivity does not typically approach zero at zero concentration; instead, it approaches a specific value based on the ions in solution.

3. Standard Molar Conductivity:

This term can refer to the molar conductivity of a standard solution, but it does not specifically relate to the behavior as concentration approaches zero.

4. Limiting Molar Conductivity (\( \Lambda_m^0 \)):

Limiting molar conductivity refers to the molar conductivity of an electrolyte when its concentration approaches zero. At this point, the ions are sufficiently far apart that they do not interact significantly with each other, and their contribution to conductivity can be considered independently. It represents the maximum conductivity achievable by the electrolyte.

Therefore, the correct answer is: Limiting molar conductivity.