1. What is pOH?

pOH is a measure of the hydroxide ion (OH⁻) concentration in a solution. It's the negative logarithm (base 10) of the hydroxide ion concentration and is used to express the alkalinity of a solution.

2. How Does the Calculator Work?

The calculator uses the pOH formula:

Where:

• \( [OH^-] \) — Hydroxide ion concentration in moles per liter (M)
• \( \log_{10} \) — Logarithm base 10

3. Relationship Between pH and pOH

In aqueous solutions at 25°C, the sum of pH and pOH is always 14: \[ pH + pOH = 14 \] This relationship allows you to calculate pH if you know pOH and vice versa.

4. Using the Calculator

Tips: Enter the hydroxide ion concentration in molarity (M). The value must be greater than 0. For very small concentrations, scientific notation may be helpful (e.g., 1×10⁻⁷ M).

5. Frequently Asked Questions (FAQ)

Q1: What is a normal pOH value?
A: In neutral water at 25°C, pOH is 7. Values below 7 indicate alkaline solutions, while values above 7 indicate acidic solutions.

Q2: How is pOH different from pH?
A: pH measures hydrogen ion concentration while pOH measures hydroxide ion concentration. They are inversely related in aqueous solutions.

Q3: Can pOH be negative?
A: Yes, pOH can be negative for very high hydroxide ion concentrations (>1 M), just like pH can be negative for very high hydrogen ion concentrations.

Q4: What are the units of pOH?
A: pOH is unitless as it's the logarithm of a concentration ratio.

Q5: When would I need to calculate pOH?
A: pOH is useful in acid-base chemistry, particularly when working with strong bases or when hydroxide concentration is more readily available than hydrogen ion concentration.