Arrhenius Model
Acids produce H⁺ ions and bases produce OH⁻ ions in aqueous solution.
Brønsted-Lowry Model
Acids are proton (H⁺) donors, and bases are proton acceptors.
Conjugate Acid
Formed when a base gains a proton (H⁺).
Conjugate Base
Formed when an acid loses a proton (H⁺).
Conjugate Acid/Base Pair
Two substances that differ by one proton (e.g., NH₃/NH₄⁺).
Monoprotic
An acid that donates one proton per molecule (e.g., HCl).
Diprotic
An acid that donates two protons per molecule (e.g., H₂SO₄).
Triprotic
An acid that donates three protons per molecule (e.g., H₃PO₄).
Weak Acid
An acid that only partially ionizes in solution.
Weak Base
A base that only partially accepts protons in solution.
Neutral Solution
A solution with equal concentrations of H₃O⁺ and OH⁻; pH = 7.
Hydronium Ion (H₃O⁺)
A water molecule with an extra proton (H⁺); the form of H⁺ in water.
Neutralization Reaction
Reaction of an acid and a base to form water and a salt.
Self-Ionization of Water
2 H₂O ⇌ H₃O⁺ + OH⁻
Ion Product Constant for Water (K₁)
K₁ = [H₃O⁺][OH⁻] = 1.0 × 10⁻¹⁴ at 25°C.
Titration
Lab method to find the unknown concentration of a solution using a solution of known concentration.
Equivalence Point
The point in a titration where moles of acid = moles of base.
Titration Curve
Graph of pH vs. volume of titrant; shows how pH changes during titration.