Water potential is maximum in case of

Options

A. Pure water
B. `2%`glucose
C. `10%`glucose
D. `10%` NaCl

Answer

### Step-by-Step Solution:

1. **Understanding Water Potential**: Water potential (Ψ) is a measure of the potential energy of water in a system and is influenced by solute concentration and pressure. It is expressed in units of pressure (usually in megapascals, MPa).

2. **Water Potential of Pure Water**: The water potential of pure water is defined as zero (Ψ = 0). This serves as a reference point on the water potential scale.

3. **Effect of Solutes on Water Potential**: When solutes (like glucose or NaCl) are added to water, they decrease the number of free water molecules in the solution. This results in a decrease in water potential, making it more negative. The more solute that is added, the lower (more negative) the water potential becomes.

4. **Comparing Water Potentials**: On the water potential scale, pure water has the highest water potential (0 MPa), while solutions with solutes have lower (negative) water potentials. Thus, as solute concentration increases, water potential decreases.

5. **Conclusion**: Since pure water has the highest water potential (maximum), it is the correct answer to the question.

### Final Answer:
Water potential is maximum in the case of **pure water**.