1. What is pH and pOH?

pH and pOH are measures of the acidity and basicity of a solution. pH is the negative logarithm of the hydrogen ion concentration, while pOH is the negative logarithm of the hydroxide ion concentration. In water at 25°C, they always add up to 14.

2. How Does the Calculator Work?

The calculator uses the fundamental relationship:

Where:

• \( \text{pH} = -\log[\text{H}^+] \) — Measure of acidity
• \( \text{pOH} = -\log[\text{OH}^-] \) — Measure of basicity
• 14 — Constant at 25°C for water

Explanation: This relationship comes from the ion product of water (Kw = [H+][OH-] = 1×10⁻¹⁴ at 25°C).

3. Importance of pH and pOH

Details: pH is critical in many chemical and biological processes. It affects enzyme activity, chemical solubility, and biological functions. pOH is useful when working with basic solutions.

4. Using the Calculator

Tips: Enter either pH or pOH value (between 0-14), and the calculator will compute the other value. Both fields can't be filled simultaneously.

5. Frequently Asked Questions (FAQ)

Q1: Why does pH + pOH equal 14?
A: This comes from the ion product of water (Kw = [H+][OH-] = 1×10⁻¹⁴ at 25°C). Taking negative logs gives pH + pOH = pKw = 14.

Q2: Does this relationship hold at all temperatures?
A: No, the constant changes with temperature. At 37°C (body temperature), pH + pOH ≈ 13.6.

Q3: What is a neutral pH?
A: At 25°C, neutral pH is 7 (equal concentrations of H+ and OH-). The neutral point changes with temperature.

Q4: How precise are pH measurements?
A: pH meters typically have ±0.01 precision. For most applications, 2 decimal places are sufficient.

Q5: Can I use this for non-aqueous solutions?
A: No, this relationship is specific for aqueous solutions. Other solvents have different ion products.