Solubility Rules

IGCSE Edexcel Chemistry
2.34 Solubility of ionic compounds
Key Concept: Nitrates are soluble, sodium and potassium salts are soluble, and most chlorides are soluble except silver and lead.

Section A: Predicting Solubility

1. Predict whether each compound is soluble in water. [4]

a) Sodium nitrate

b) Silver chloride

c) Lead sulfate

d) Potassium carbonate

2. State two general solubility rules. [2]
3. Explain why calcium carbonate is insoluble but calcium nitrate is soluble. [2]

Total marks: 8

Mark Scheme

1. a) Soluble b) Insoluble c) Insoluble d) Soluble [4]
2. Any two: all nitrates soluble; all sodium/potassium/ammonium salts soluble; most chlorides soluble except AgCl/PbCl2; most sulfates soluble except BaSO4/PbSO4/CaSO4 [2]
3. Nitrates are soluble; carbonates are mostly insoluble except sodium/potassium/ammonium [2]