Hydrogen Ion Concentration Calculator

Free calculate hydrogen ion concentration [h⁺], ph, poh, and hydroxide ion concentration for acids and bases.

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pH

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Enter solution data to calculate ion concentrations

pH and Ion Concentration Formulas

pH and pOH

pH = -log[H⁺]

pOH = -log[OH⁻]

pH + pOH = 14

  • • [H⁺] = 10^(-pH)
  • • [OH⁻] = 10^(-pOH)
  • • Kw = [H⁺][OH⁻] = 1×10⁻¹⁴
  • • pH < 7: Acidic
  • • pH > 7: Basic

Weak Acid/Base

[H⁺] = √(Ka × [HA])

[OH⁻] = √(Kb × [B])

  • • Ka = Acid dissociation constant
  • • Kb = Base dissociation constant
  • • Ka × Kb = Kw
  • • Valid for dilute solutions
  • • Assumes negligible ionization

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