Weak Acid Equilibrium and Ka
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A weak acid ionizes only partially in water, and Ka, its acid ionization constant, measures how far that equilibrium favors ions over the intact acid.
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Acetic acid's Ka expression is [H3O+][CH3COO−]/[CH3COOH], a genuine equilibrium rather than a completed reaction.
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Water does not belong in the Ka expression's denominator, and a weak acid's ionization is not complete, so molarity cannot substitute for [H3O+].
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- 1841 The Ka–Kb Relationship for a Conjugate Pair
- 1844 Solving for pH of a Weak Acid Solution
- 1847 Percent Ionization Defined
- 1853 Polyprotic Acids: Stepwise Ionization
- 1865 Acid-Base Indicators: Mechanism
- 1887 Buffers: How They Resist pH Change
- 1893 Henderson-Hasselbalch Equation Application
- 1899 Capstone: Buffer pH Calculation