Water potential of pure water at standard temperature is equal to

Options

A. 10
B. 20
C. Zero
D. None of these

Answer

To solve the question regarding the water potential of pure water at standard temperature, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Water Potential**:
- Water potential (Ψ) is a measure of the potential energy of water in a system, influencing the movement of water. It is determined by the concentration of solutes and the pressure exerted on the water.

2. **Water Potential of Pure Water**:
- The water potential of pure water at standard temperature and pressure (STP) is defined as zero. This is because pure water has no solutes, which means there is no reduction in free energy due to solute presence.

3. **Formula for Water Potential**:
- Water potential can be calculated using the formula:
\[ Ψ = Ψ_s + Ψ_p \]
where Ψ_s is the solute potential (which is zero for pure water) and Ψ_p is the pressure potential (which can also be zero if there is no pressure applied).

4. **Conclusion**:
- Since pure water has no solutes, its solute potential (Ψ_s) is zero. Therefore, the water potential (Ψ) of pure water is:
\[ Ψ = 0 + 0 = 0 \]

5. **Final Answer**:
- The water potential of pure water at standard temperature is equal to **0**.