🧪 Acid-Base Equilibrium & Water Autoionization
pH, pOH & $[H^+]$ / $[OH^-]$ Calculator
Convert seamlessly between pH, pOH, hydronium ion $[H_3O^+]$ concentration, and hydroxide $[OH^-]$ concentration with acid/base classification and logarithmic scale visualization.
🍋 Gastric Acid (pH 1.0)
🍋 Lemon Juice (pH 2.4)
🥗 Vinegar (pH 3.0)
☕ Coffee (pH 5.0)
💧 Neutral Water (pH 7.0)
🩸 Human Blood (pH 7.4)
🧼 Bleach (pH 12.5)
Enter Known Parameter
0 (Strong Acid)
7 (Neutral)
14 (Strong Base)
Solution Classification
pH = 7.40
pH
7.40
pOH
6.60
[H⁺] / [H₃O⁺] Concentration
3.98 × 10⁻⁸ M
[OH⁻] Concentration
2.51 × 10⁻⁷ M
💡 Ion Product of Water ($K_w$):
$$[H^+][OH^-] = 1.0 \times 10^{-14} \implies \text{pH} + \text{pOH} = 14.00$$
Acid-Base Equilibrium Mathematics
Søren Sørensen introduced the logarithmic pH scale in 1909:
- pH: $$\text{pH} = -\log_{10}[H_3O^+] \iff [H_3O^+] = 10^{-\text{pH}}$$
- pOH: $$\text{pOH} = -\log_{10}[OH^-] \iff [OH^-] = 10^{-\text{pOH}}$$
- Water Self-Ionization ($25^\circ\text{C}$): $$K_w = [H^+][OH^-] = 1.0 \times 10^{-14} \implies \text{pH} + \text{pOH} = 14.00$$