Maximum water potential is present in
(a) Hypotonic solution
(b) Hypertonic solution
(c) Isotonic solution
(d) Pure water

Options

A. Hypotonic solution
B. Hypertonic solution
C. Isotonic solution
D. Pure water

Answer

To solve the question regarding which solution has the maximum water potential, let's break it down step by step:

### Step-by-Step Solution:

1. **Understanding Water Potential**:
- Water potential (Ψ) is a measure of the potential energy in water and is influenced by the concentration of solutes. It is expressed in units of pressure (usually megapascals, MPa).
- The water potential of pure water is defined as 0 MPa, which is the highest possible value.

2. **Analyzing the Options**:
- **(a) Hypotonic solution**: This solution has a lower concentration of solutes compared to the inside of a cell, which means it has a higher concentration of water molecules. However, it still contains some solutes, so its water potential is less than that of pure water.
- **(b) Hypertonic solution**: This solution has a higher concentration of solutes compared to the inside of a cell, leading to a lower concentration of water molecules. Thus, it has a negative water potential.
- **(c) Isotonic solution**: This solution has an equal concentration of solutes compared to the inside of a cell. It has a water potential that is lower than pure water but higher than hypertonic solutions.
- **(d) Pure water**: As mentioned earlier, pure water has no solutes and thus has the highest water potential, which is 0 MPa.

3. **Conclusion**:
- Among all the options, pure water has the maximum water potential because it contains no solutes, which means it has the highest concentration of water molecules.

### Final Answer:
- The correct answer is **(d) Pure water**.