Which of the following statements is/are correct?

Options

A. The conductance of one `cm^(3)` (or `1unit^(3))` of a solution is called conductivity.
B. Specific conductance increases while molar conductivity decreases on progressive dilution.
C. The limiting equivalent conductivity of weak electrolyte cannote bee determine exactly by extraplotation of the plot of `^^_(eq)` against `sqrt(c)`.
D. The condcutance of metals is due to the movement of free electrons.

Answer

To solve the question regarding the correctness of the given statements about electrochemistry, we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Understanding Specific Conductance**:
- Specific conductance (or conductivity) is defined as the conductance of a solution when it is contained in a unit cube (1 cm³) with a length of 1 cm and a cross-sectional area of 1 cm².
- This means that specific conductance is a measure of how well a solution can conduct electricity.

**Hint**: Remember that specific conductance is related to the dimensions of the conductor and the nature of the solution.

2. **Behavior of Conductivity with Dilution**:
- It is known that as a solution is progressively diluted, the specific conductance (or conductivity) decreases while the molar conductivity increases. This is because dilution reduces the number of ions per unit volume, thus decreasing conductivity, but increases the ability of each ion to contribute to conductivity (molar conductivity).

**Hint**: Think about how dilution affects the concentration of ions in the solution.

3. **Limiting Equivalent Conductivity of Weak Electrolytes**:
- The limiting equivalent conductivity of weak electrolytes cannot be determined exactly by extrapolation from a graph of conductivity versus concentration. This is because weak electrolytes do not fully dissociate in solution, leading to difficulties in accurately determining their limiting behavior.

**Hint**: Consider the difference between strong and weak electrolytes in terms of dissociation.

4. **Conductance of Metals**:
- The conductance of metals is primarily due to the movement of free electrons. In metals, electrons are not bound to any particular atom and can move freely, which allows them to conduct electricity efficiently.

**Hint**: Recall the role of free electrons in metallic bonding and conductivity.

### Conclusion:
Based on the analysis of each statement:
- The correct statements are:
- The definition of specific conductance.
- The behavior of specific conductance and molar conductivity upon dilution.
- The nature of conductance in metals.

Thus, the answer to the question is that statements C and D are correct.

### Final Answer:
The correct statements are C and D.