Acids, Bases & Salts
8 terms
pH
Acids, Bases & Salts
Dimensionless
The negative logarithm to base ten of the hydrogen ion concentration, measuring the acidity of a solution.
pH = −log[H⁺]
pH Scale
Acids, Bases & Salts
Dimensionless
The conventional scale, usually running from 0 to 14, on which the acidity or alkalinity of aqueous solutions is expressed.
0 (acidic) – 7 (neutral) – 14 (alkaline)
Phenolphthalein
Acids, Bases & Salts
Dimensionless
An acid–base indicator that is colourless in acid and pink in alkaline solution, changing between pH 8.3 and 10.0.
C₂₀H₁₄O₄
pKa
Acids, Bases & Salts
Dimensionless
The negative logarithm of the acid dissociation constant, giving a convenient scale of acid strength.
pKa = −log Ka
pKb
Acids, Bases & Salts
Dimensionless
The negative logarithm of the base dissociation constant.
pKb = −log Kb
pOH
Acids, Bases & Salts
Dimensionless
The negative logarithm of the hydroxide ion concentration.
pOH = −log[OH⁻]; pH + pOH = 14
Polyprotic Acid
Acids, Bases & Salts
mol/L
An acid capable of donating more than one proton per molecule.
H₂A ⇌ H⁺ + HA⁻ ⇌ 2H⁺ + A²⁻
Proton Affinity
Acids, Bases & Salts
kJ/mol
The energy released when a gaseous species accepts a proton, measuring intrinsic basicity free of solvent effects.
B(g) + H⁺(g) → BH⁺(g)