What is pOH?

The term pOH stands for the "potential of hydroxide ions." It is a chemical measurement used to determine the alkalinity (basicity) of an aqueous solution. Mathematically, pOH is defined as the negative logarithm (base 10) of the hydroxide ion concentration [OH⁻]. While pH is the standard measure for acidity, pOH offers a complementary perspective, specifically focusing on the concentration of hydroxide ions in a liquid.

How to Calculate pOH

Calculating pOH is straightforward if you know either the hydroxide concentration or the pH of the solution. The fundamental formula is:

pOH = -log₁₀[OH⁻]

If you are working at a standard temperature of 25°C (298 K), the relationship between pH and pOH is constant: pH + pOH = 14. This means if you know the pH of a solution is 9, the pOH must be 5 (14 - 9 = 5).

Steps to Use the pOH Calculator

To use this tool effectively, follow these steps:

1. Input Hydroxide Concentration: Enter the [OH⁻] in moles per liter. You can use scientific notation (e.g., 1e-7).
2. Input pOH directly: If you already have the pOH and want to find the [OH⁻] or pH, enter it in the second box.
3. Analyze Results: The calculator will show you the corresponding pH and classify the solution as Acidic, Basic, or Neutral.

FAQs about pOH

Is a high pOH acidic or basic? A high pOH value (greater than 7) indicates an acidic solution. Conversely, a low pOH value (less than 7) indicates a basic solution. This is the inverse of the pH scale logic.

Can pOH be negative? Yes, in extremely concentrated basic solutions where the hydroxide ion concentration exceeds 1 M, the pOH can drop below zero.