Frequently Asked Questions
What is pH?
pH is the negative base-10 logarithm of the hydrogen ion concentration ([H⁺]). It measures how acidic or basic a solution is: pH 7 is neutral, below 7 is acidic, and above 7 is basic.
What is the relationship between pH and pOH?
At 25°C, pH + pOH = 14. Knowing one lets you calculate the other: pOH = 14 - pH.
How does pH calculation differ for strong vs. weak acids?
Strong acids fully ionize, so [H⁺] equals the acid concentration directly. Weak acids require equilibrium calculations using the acid dissociation constant (Ka).
2026 physical constants