pH = 3.60 — acidic
- pH
- 3.602
- pOH
- 10.398
- [H⁺]
- 2.50 × 10⁻⁴ M
- [OH⁻]
- 4.00 × 10⁻¹¹ M
All values assume 25 °C, where pH + pOH = 14.
How it works
Strong acids and bases are treated as fully dissociated, but the calculator solves [H⁺]² − C[H⁺] − Kw = 0 instead of simply setting [H⁺] = C, so it stays correct even near neutral. Weak acids and bases use the full equilibrium quadratic x² + Kx − KC = 0. All results assume 25 °C (Kw = 1.0 × 10⁻¹⁴) and ideal behaviour, which is accurate for dilute solutions.
Frequently asked questions
- How do you calculate pH?
- pH = −log₁₀[H⁺], where [H⁺] is the hydrogen-ion (hydronium) concentration in mol/L. A solution with [H⁺] = 0.001 M has pH 3.
- How are pH and pOH related?
- At 25 °C, pH + pOH = 14, because [H⁺] × [OH⁻] = 1.0 × 10⁻¹⁴ in any water solution. Knowing one of the four values — pH, pOH, [H⁺] or [OH⁻] — gives all the others.
- Why is the pH of 10⁻⁸ M HCl not 8?
- An acid can never make water basic. At such low concentration, the H⁺ from water itself (10⁻⁷ M) outweighs the acid’s contribution, and the correct pH is about 6.98. This calculator includes water’s own ions, so it gets this right.
- How do you find the pH of a weak acid?
- Use its Ka: for a concentration C, the H⁺ concentration x satisfies x² / (C − x) = Ka. The calculator solves this quadratic exactly rather than using the x ≪ C shortcut, which fails for dilute solutions or larger Ka values.
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