What is water potential of pure water at atmospheric pressure? What happens to it when solutes are added to it?

Explanation

### Step-by-Step Solution:

1. **Understanding Water Potential**: Water potential is a measure of the potential energy of water in a system and is influenced by factors such as pressure and solute concentration. It is denoted by the symbol Ψ (psi).

2. **Water Potential of Pure Water**: At atmospheric pressure, the water potential of pure water is defined as zero (Ψ = 0). This is because pure water has the highest concentration of free water molecules, resulting in maximum kinetic energy.

3. **Effect of Adding Solutes**: When solutes are added to pure water, the concentration of free water molecules decreases. The solute molecules bind with water molecules, reducing the number of free water molecules available.

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