GRADE 12 PHYSICAL SCIENCES
Acids, Bases & Titration – Detailed Notes
1. Acids and Bases Theories
Arrhenius Theory:
1 Acid: Produces H+ ions in aqueous solution
2 Base: Produces OH- ions in aqueous solution
Brønsted-Lowry Theory:
1 Acid: Proton (H+) donor
2 Base: Proton (H+) acceptor
3 Conjugate acid-base pairs form during reactions
Example:
HCl + H2O → H3O+ + Cl-
2. Strong vs Weak Acids and Bases
1 Strong acids fully ionise in water (HCl, HNO3)
2 Weak acids partially ionise (CH3COOH)
3 Strong bases: NaOH, KOH
4 Weak bases: NH3
Important: Strength is not the same as concentration.
3. pH and Calculations
1 pH < 7: Acidic
2 pH = 7: Neutral
3 pH > 7: Basic
Formula: pH = -log[H+]
Example: If [H+] = 1×10^-3, then pH = 3
4. Neutralisation Reactions
General equation:
Acid + Base → Salt + Water
Example: HCl + NaOH → NaCl + H2O
Net ionic equation: H+ + OH- → H2O
Acids, Bases & Titration – Detailed Notes
1. Acids and Bases Theories
Arrhenius Theory:
1 Acid: Produces H+ ions in aqueous solution
2 Base: Produces OH- ions in aqueous solution
Brønsted-Lowry Theory:
1 Acid: Proton (H+) donor
2 Base: Proton (H+) acceptor
3 Conjugate acid-base pairs form during reactions
Example:
HCl + H2O → H3O+ + Cl-
2. Strong vs Weak Acids and Bases
1 Strong acids fully ionise in water (HCl, HNO3)
2 Weak acids partially ionise (CH3COOH)
3 Strong bases: NaOH, KOH
4 Weak bases: NH3
Important: Strength is not the same as concentration.
3. pH and Calculations
1 pH < 7: Acidic
2 pH = 7: Neutral
3 pH > 7: Basic
Formula: pH = -log[H+]
Example: If [H+] = 1×10^-3, then pH = 3
4. Neutralisation Reactions
General equation:
Acid + Base → Salt + Water
Example: HCl + NaOH → NaCl + H2O
Net ionic equation: H+ + OH- → H2O
