CAIE IGCSE Chemistry Soluble and Insoluble Salts

Practise applying nitrate, chloride, sulfate, carbonate and hydroxide solubility rules to choose reagents, predict precipitates and assign state symbols.

Exam points

treat all nitrates and all sodium, potassium or ammonium salts as soluble in water
apply the named chloride and sulfate exceptions when predicting an insoluble product
use carbonate and hydroxide exceptions to select reagent pairs and correct state symbols

[Maximum number: 1]

Sulfur is an important element.

Dilute sulfuric acid is used to make salts known as sulfates.

A method consisting of three steps is used to make zinc sulfate from zinc carbonate.
step 1 Add an excess of zinc carbonate to $20 \mathrm{~cm}^{3}$ of $0.4 \mathrm{~mol} / \mathrm{dm}^{3}$ dilute sulfuric acid until the reaction is complete.
step 2 Filter the mixture.
step 3 Heat the filtrate until a saturated solution forms and then allow it to crystallise.

Suggest why this method would not work to make barium sulfate from barium carbonate and dilute sulfuric acid.

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7.3.2—Salt solubility rules: soluble question 1