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 solve the question "Which of the following is not correct?" regarding the properties of conductance in solutions, we will analyze each option step by step.

### Step 1: Analyze the first option
**Statement**: Molar conductance of a solution increases with dilution.

**Explanation**: This statement is correct. When a solution is diluted, the concentration of ions decreases, but the total number of ions in the solution increases due to the increase in volume. This leads to an increase in molar conductance.

### Step 2: Analyze the second option
**Statement**: Equivalent conductance increases with dilution.

**Explanation**: This statement is also correct. As the solution is diluted, the number of ions per unit volume increases, which results in an increase in equivalent conductance.

### Step 3: Analyze the third option
**Statement**: Specific conductance increases with dilution.

**Explanation**: This statement is incorrect. When a solution is diluted, the number of ions per unit volume decreases, which leads to a decrease in specific conductance. Therefore, this option is the one that is not correct.

### Step 4: Analyze the fourth option
**Statement**: At infinite dilution, each ion (cation or anion) plays a definite role towards electrical conductance.

**Explanation**: This statement is correct. At infinite dilution, the equivalent conductivity of an electrolyte is the sum of the equivalent conductivities of its cations and anions, as per Kohlrausch's law.

### Conclusion
Based on the analysis, the statement that is not correct is the third option: "Specific conductance increases with dilution."

### Final Answer
The answer is **C**: Specific conductance increases with dilution.

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