IGCSE Chemistry
2026 - 2028
Syllabus Checklist ✅
Topic 13: Acids, Bases and Salts
Characteristic Properties of Acids
Describe the characteristic properties of acids
in terms of their reactions with: (a) metals
(b) bases
(c) carbonates
Describe acids by their effect on indicators: (a) litmus
(b) thymolphthalein
(c) methyl orange
Characteristic Properties of Bases and Alkalis
State that bases
are oxides or hydroxides of metals and that alkalis
are soluble bases
Describe the characteristic properties of bases
in terms of their reactions with: (a) acids
(b) ammonium salts
Describe alkalis
by their effect on indicators: (a) litmus
(b) thymolphthalein
(c) methyl orange
Ion Theory and Strength of Acids and Bases
State that aqueous solutions of acids contain H⁺ ions
and aqueous solutions of alkalis contain OH⁻ ions
Define acids
as proton donors
and bases
as proton acceptors
Define a strong acid
as completely dissociated in aqueous solution and a weak acid
as partially dissociated
State that hydrochloric acid
is a strong acid, and ethanoic acid
is a weak acid, as shown by their symbol equations
pH and Neutralisation
Describe how to compare H⁺ concentration
, neutrality, relative acidity and alkalinity using universal indicator paper
and pH scale
Describe the neutralisation reaction
between an acid
and an alkali
to produce water
Oxides
Classify oxides
as acidic
(e.g. SO₂, CO₂) or basic
(e.g. CuO, CaO) in relation to metallic and non-metallic character
Describe amphoteric oxides
as oxides that react with both acids and bases to produce a salt
and water
Classify Al₂O₃
and ZnO
as amphoteric oxides
Preparation of Salts
Describe preparation, separation and purification of soluble salts
by reaction of an acid with: (a) an alkali
by titration
(b) excess metal
(c) excess insoluble base
(d) excess insoluble carbonate
Describe the general solubility rules
for salts:
(a) Na⁺, K⁺ and NH₄⁺ salts are soluble
(b) Nitrates
are soluble
(c) Chlorides
are soluble except lead
and silver
(d) Sulfates
are soluble except barium
, calcium
, lead
(e) Carbonates
are insoluble except Na⁺, K⁺, NH₄⁺
(f) Hydroxides
are insoluble except Na⁺, K⁺, NH₄⁺ and Ca²⁺ (partially)
Define a hydrated substance
as one chemically combined with water and an anhydrous substance
as one containing no water
Describe preparation of insoluble salts
by precipitation
Define water of crystallisation
as the water molecules present in hydrated crystals
, e.g. CuSO₄·5H₂O
and CoCl₂·6H₂O
