Question

The water potential of pure water at atmospheric pressure is

• A. Zero bar
• B. +2.3 bar
• C. One bar
• D. $-2.3$ bar

Hint:

Pure water always has the highest water potential, defined as zero.

Answer 1

The Correct Option is A

Step 1: Water potential (\( \Psi_w \)) is a measure of the free energy of water.
Step 2: By convention, the water potential of pure water at atmospheric pressure and standard temperature is taken as zero.
Step 3: Solutions have lower (more negative) water potential compared to pure water. Hence, the water potential of pure water at atmospheric pressure is zero bar.