Which is the correct representation to express the molar concentration (M) of any solution ?

Options

A. `("No.of gram equivalent of solute")/("Volume of solution in litre")`
B. `("No.of moles of solute")/("Volume of solution in litre")`
C. `("No.of moles of solute")/("Mass of solvent in kg")`
D. `("No.of moles of any constituent")/("Total no.of moles of all constituents")`

Answer

To determine the correct representation for expressing the molar concentration (M) of any solution, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Molar Concentration**: Molar concentration, also known as molarity (M), is defined as the number of moles of solute per liter of solution. The formula for molarity is:
\[ M = \frac{\text{Number of moles of solute}}{\text{Volume of solution in liters}} \]

2. **Analyze the Options**: The question provides multiple options (A, B, C, D). We need to evaluate each option to see which one correctly represents molarity.

3. **Evaluate Each Option**:
- **Option A**: If this option states something other than the formula for molarity, we can discard it.
- **Option B**: If this option states that molarity is the number of moles of solute divided by the volume of solution in liters, then this is the correct representation of molarity.
- **Option C**: If this option refers to the number of moles of solute divided by the mass of solvent in kilograms, this represents molality, not molarity.
- **Option D**: If this option refers to the mole fraction, which is the ratio of the number of moles of a component to the total number of moles of all components, this is also not molarity.

4. **Identify the Correct Option**: After evaluating all options, if Option B correctly states the relationship for molarity, then we conclude that Option B is the correct representation for molar concentration.

5. **Final Conclusion**: Therefore, the correct representation to express the molar concentration (M) of any solution is:
\[ \text{Molarity (M)} = \frac{\text{Number of moles of solute}}{\text{Volume of solution in liters}} \]
Hence, the answer is **Option B**.