Acids and bases

Need to know

What you need to know

• A larger Ka value indicates a greater extent of dissociation and therefore a stronger acid.
• pKa is used for convenience: $pK_a = -log_{10}(K_a)$.
• A smaller pKa value indicates a stronger acid.
• The ionic product of water, $K_w = [H^+][OH^-] = 1.0 \times 10^{-14} \ mol^2 \ dm^{-6}$ at 298 K, links the concentrations of H⁺ and OH⁻ in any aqueous solution.

Explanation

The Proton Dance

1. Brønsted–Lowry: acid proton donor, base proton acceptor.
2. Ka, pKa, pH — weak acid partial dissociation.
3. Buffer resists pH change — weak acid + conjugate base.
4. Titration curves — equivalence point pH depends on acid/base strength.