Which of the following is not correct?

Options

A. Molar conductance of a solution increases with dilution
B. Equivalent conductance increases with dilution
C. Specific conductance increases with dilution
D. At infinite dilution each ion (cation or anion) plays a definite role towards electrical conductance

Answer

To determine which statement is not correct regarding the effects of dilution on conductance in electrochemistry, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement 1: Molar conductance solution increases with dilution.**
- Molar conductance (Λ) is defined as the conductance of a solution divided by its molarity. When a solution is diluted, the number of ions per unit volume decreases, but the increase in the distance between ions reduces the force of attraction, allowing ions to move more freely. Thus, molar conductance increases with dilution.
- **Conclusion:** This statement is correct.

2. **Statement 2: Equivalent conductance increases with dilution.**
- Equivalent conductance (Λ_eq) is the conductance of an electrolyte solution divided by the number of equivalents of the solute. Similar to molar conductance, as the solution is diluted, the equivalent conductance also increases due to the same reasons mentioned above (increased ease of ion movement).
- **Conclusion:** This statement is correct.

3. **Statement 3: Specific conductance increases with dilution.**
- Specific conductance (κ) is defined as the conductance of a solution per unit length and unit area. When a solution is diluted, the concentration of ions decreases, leading to a decrease in specific conductance. Therefore, specific conductance does not increase with dilution; it actually decreases.
- **Conclusion:** This statement is incorrect.

4. **Statement 4: Infinite dilution.**
- At infinite dilution, the ions are far enough apart that their interactions are negligible, and each ion contributes to the conductance independently. This statement is generally accepted in electrochemistry.
- **Conclusion:** This statement is correct.

5. **Statement 5: Either it is cation or anion. Play the definite role towards electrical conductance.**
- This statement reflects the principle that both cations and anions contribute to electrical conductance in a solution. Both types of ions are essential for the conduction of electricity in electrolytic solutions.
- **Conclusion:** This statement is correct.

### Final Answer:
The statement that is not correct is **Statement 3: Specific conductance increases with dilution.**