Isotonic solutions have same

Options

A. vapour pressure
B. freezing temperature
C. osmotic pressure
D. boiling temperature

Answer

To solve the question "Isotonic solutions have same," we need to analyze the provided options and understand the concept of isotonic solutions.

### Step-by-Step Solution:

1. **Understanding Isotonic Solutions**:
- Isotonic solutions are solutions that have the same osmotic pressure. This means that when two solutions are separated by a semipermeable membrane, there will be no net movement of solvent molecules across the membrane.

2. **Analyzing the Options**:
- **Option 1: Vapor Pressure**:
- Vapor pressure refers to the pressure exerted by a vapor in equilibrium with its liquid or solid phase. Isotonic solutions do not necessarily have the same vapor pressure.
- **Option 2: Freezing Temperature**:
- The freezing point is the temperature at which a liquid turns into a solid. Isotonic solutions do not have the same freezing point.
- **Option 3: Osmotic Pressure**:
- Osmotic pressure is the pressure required to prevent the flow of solvent into a solution through a semipermeable membrane. Isotonic solutions have the same osmotic pressure.
- **Option 4: Boiling Temperature**:
- The boiling point is the temperature at which a liquid turns into gas. Isotonic solutions do not necessarily have the same boiling temperature.

3. **Conclusion**:
- Based on the definitions and analysis of the options, the correct answer is **Option 3: Osmotic Pressure**. Isotonic solutions have the same osmotic pressure.

### Final Answer:
Isotonic solutions have the same **osmotic pressure**.