Acids, equilibrium & kinetics · SL/HL

pH ↔ [H⁺]

Convert between pH and hydrogen-ion concentration.

Your values

Number formats & units

Use decimal dots in datasets. Single values also accept decimal commas and scientific notation such as 1.2e-3 or 1.2 × 10⁻³.

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Example

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\mathrm{pH}=-\log_{10}[\mathrm H^+]

[\mathrm H^+]=10^{-\mathrm{pH}}

What the variables mean

Symbol	Meaning
[ $H^{+}$ ]	Hydrogen-ion concentration used by the course model.

pH = 3

Follow the example steps

The pH definition uses a base-10 logarithm.

[H⁺] = 0.001 mol dm⁻³: pH = −ln(0.001) ≈ 6.908

pH = −log₁₀(0.001) = 3

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Method notes

The logarithmic scale means a change of one pH unit corresponds to a factor of ten in [H⁺].