Ka/Kb Calculator - Calculator Suite

Ka Calculator (Acid Strength)

Initial Acid Concentration (M):

H⁺ Concentration at Equilibrium (M):

Or enter pH:

Acid Formula (optional):

Kb Calculator (Base Strength)

Initial Base Concentration (M):

OH⁻ Concentration at Equilibrium (M):

Or enter pOH:

Base Formula (optional):

Ka ⇌ Kb Relationship

Known Value:

Value:

Temperature (°C):

Common Acids & Bases Lookup

Select Compound:

Ka/Kb Reference Guide

Key Relationships:

Ka × Kb = Kw = 1.0 × 10⁻¹⁴ (at 25°C)

pKa + pKb = 14.00 (at 25°C)

Acid/Base Strength Classification:

Strong Acids:

Ka > 1, pKa < 0

Complete ionization

Strong Bases:

Kb > 1, pKb < 0

Complete ionization

Weak Acids:

Ka < 1, pKa > 0

Partial ionization

Weak Bases:

Kb < 1, pKb > 0

Partial ionization

Common Ka Values (25°C):

CH₃COOH
Ka = 1.8 × 10⁻⁵

HF
Ka = 6.8 × 10⁻⁴

HCOOH
Ka = 1.8 × 10⁻⁴

HCN
Ka = 4.9 × 10⁻¹⁰

Calculation Formulas:

For monoprotic acid: Ka = [H⁺][A⁻]/[HA]

For weak base: Kb = [BH⁺][OH⁻]/[B]

Percent ionization: α = √(Ka/C₀) × 100%

pH from Ka: pH = ½(pKa - log C₀)

⚗️ Ka/Kb Calculator