Isotonic solutions have same

Options

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

Answer

To solve the question regarding isotonic solutions, we need to understand the concept of isotonicity and the properties that are equal in such solutions.

### Step-by-Step Solution:

1. **Definition of Isotonic Solutions**:
- Isotonic solutions are those 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 between them.

2. **Understanding Osmotic Pressure**:
- Osmotic pressure is the pressure required to prevent the flow of solvent into a solution through a semipermeable membrane. It is a colligative property, which means it depends on the number of solute particles in the solution rather than the identity of the solute.

3. **Comparison with Other Properties**:
- While isotonic solutions have the same osmotic pressure, they may not necessarily have the same vapor pressure, freezing point, or boiling point. These properties can differ based on the nature and concentration of solutes present in the solutions.

4. **Conclusion**:
- Therefore, the correct answer to the question "Isotonic solutions have the same..." is that isotonic solutions have the same **osmotic pressure**.

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