Select an incorrect statement for water potential

Options

A. Water potential is expressed in pressure units
B. Pure water will have the lowest water potential
C. Water molecules possess kinetic energy.
D. The greater the concentration of water in a system, the greater is its kinetic energy or 'water potential'

Answer

To determine the incorrect statement regarding water potential, we can analyze the provided statements step by step:

### Step-by-Step Solution:

1. **Understanding Water Potential**:
- Water potential is a measure of the potential energy of water in a system and indicates the direction in which water will move. It is influenced by solute concentration and pressure.

2. **Kinetic Energy of Water Molecules**:
- Water molecules possess kinetic energy. The more water molecules present, the higher the kinetic energy, which contributes to a higher water potential.

3. **Water Potential of Pure Water**:
- Pure water, which contains no solutes, has the highest water potential. This is because it has the maximum number of water molecules, leading to maximum kinetic energy.

4. **Effect of Solutes on Water Potential**:
- When solutes are added to pure water, the number of free water molecules decreases, which reduces kinetic energy and consequently lowers the water potential.

5. **Evaluating the Statements**:
- **Statement 1**: Water molecules possess kinetic energy. (Correct)
- **Statement 2**: Pure water has the lowest water potential. (Incorrect)
- **Statement 3**: Greater concentration of water leads to greater kinetic energy and water potential. (Correct)
- **Statement 4**: More water molecules mean more kinetic energy and water potential. (Correct)

6. **Identifying the Incorrect Statement**:
- The second statement is incorrect because pure water has the highest water potential, not the lowest.

### Conclusion:
The incorrect statement regarding water potential is the second one: "Pure water will have the lowest water potential."

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