Question

Addition of more solutes in a given solution will:

• A. Raise its water potential
• B. Lower its water potential.
• C. Make its water potential zero
• D. Not affect the water potential at all

Answer 1

The Correct Option is B

The concept of water potential is crucial in understanding how water moves through plant tissues. Water potential (\( \Psi \)) is a measure of the potential energy in water, particularly important in osmosis, which determines the direction and rate of water movement.

Water potential is influenced by the presence of solutes and pressure. It is defined mathematically as: 

\( \Psi = \Psi_s + \Psi_p \)

Where:

• \( \Psi \) = Total water potential
• \( \Psi_s \) = Solute potential (also known as osmotic potential)
• \( \Psi_p \) = Pressure potential

Adding more solutes to a solution affects the solute potential (\( \Psi_s \)). Solute potential is always negative because solutes lower the potential of water. The addition of solutes makes the solute potential more negative, thus lowering the overall water potential (\( \Psi \)). This can be expressed as:

\( \Psi_s = - \text{number of solutes added} \)

Therefore, the correct answer is:

• Lower its water potential.