For a solution at atmospheric pressure, water potential is

Options

A. `Psi_(w) = Psi_(s) + Psi_(p)`
B. `Psi_(w) = Psi_(s)`
C. `Psi_(w) = Psi_(s) - Psi_(p)`
D. `Psi_(w) = 0`

Answer

To solve the question regarding water potential at atmospheric pressure, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Water Potential**: Water potential is a measure of the potential energy of water in a system and is influenced by two main components: solute potential and pressure potential.

2. **Identify the Components**:
- **Solute Potential (Ψs)**: This is the effect of solute concentration on the overall water potential. It is always a negative value or zero.
- **Pressure Potential (Ψp)**: This is the physical pressure exerted on the water. At atmospheric pressure, this value is typically zero.

3. **Use the Water Potential Formula**: The general formula for water potential (Ψ) is given by:
\[ Ψ = Ψs + Ψp \]

4. **Evaluate at Atmospheric Pressure**:
- At atmospheric pressure, the pressure potential (Ψp) is zero. Therefore, the formula simplifies to:
\[ Ψ = Ψs + 0 \]
This means:
\[ Ψ = Ψs \]

5. **Conclusion**: At atmospheric pressure, the water potential is equal to the solute potential. Thus, the correct answer to the question is that water potential at atmospheric pressure is equal to the solute potential.

### Final Answer:
Water potential at atmospheric pressure is equal to the solute potential.

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