Which one is correct

Options

A. Molality changes with temperature
B. Molality does not change with temperature
C. Molarity does not change with temperature
D. Normality does not change with temperature

Explanation

To solve the question regarding the temperature dependence of molality, let's break it down step by step.

### Step 1: Understanding Molality
Molality (m) is defined as the number of moles of solute per kilogram of solvent. The formula for molality is:
\[ \text{Molality (m)} = \frac{\text{Number of moles of solute}}{\text{Mass of solvent (kg)}} \]

### Step 2: Analyzing Temperature Dependence
Since molality is based on the mass of the solvent (which does not change with temperature), it is independent of temperature. This means that regardless of temperature changes, the molality of a solution will remain constant as long as the amount of solute and the mass of the solvent remain unchanged.

### Step 3: Understanding Molarity
Molarity (M), on the other hand, is defined as the number of moles of solute per liter of solution:
\[ \text{Molarity (M)} = \frac{\text{Number of moles of solute}}{\text{Volume of solution (L)}} \]
Since the volume of the solution can change with temperature (due to thermal expansion), molarity is temperature dependent.

### Step 4: Understanding Normality
Normality (N) is defined as the number of equivalents of solute per liter of solution:
\[ \text{Normality (N)} = \frac{\text{Number of equivalents of solute}}{\text{Volume of solution (L)}} \]
Like molarity, normality also depends on the volume of the solution, which can change with temperature. Therefore, normality is also temperature dependent.

### Conclusion
From the analysis:
- **Molality is temperature independent.**
- **Molarity and Normality are temperature dependent.**

Thus, the correct statement is that molality does not change with temperature, while molarity and normality do.

### Final Answer
**Molality is temperature independent.**

---