pH Calculator
Compute pH from acid/base concentration, mass+volume, or directly from [H⁺]/[OH⁻]/pOH.
Section 1: Solution Properties
Results
pH
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Step-by-step derivation
Choose a mode and enter values to see the derivation.
References
- pH = −log₁₀[H⁺], pOH = −log₁₀[OH⁻], and pH + pOH = 14 (25 °C).
- Weak acid: HA ⇌ H⁺ + A⁻ → Ka = [H⁺][A⁻]/[HA]; solve x = (−Ka + √(Ka² + 4Kac))/2.
- Weak base: BOH ⇌ B⁺ + OH⁻ → Kb = [OH⁻][B⁺]/[BOH]; analog quadratic for x = [OH⁻].
- Strong species assumed fully dissociated (stoichiometry applied).