Methods of preparation

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Salts can be prepared from several methods. Any particular method chosen depends on whether the salts are soluble or not. Soluble salts are prepared by methods which involve crystallization, while insoluble salts are prepared by methods which involve precipitation.

For chemical analysis analysts have developed a wide range of qualitative tests to detect specific chemicals which may be molecules or ions. Chemical tests are based on reactions that produce a gas with distinctive properties, or a colour change produced by adding a reagent or the production of an insoluble solid that appears as a precipitate.

Apart from knowing how to make salts, you need to know how to identify salts and other compounds from their constituent ions. There is no single test for a salt, you must do at least two tests to confirm the identity of the two constituent ions. Most of the methods described below are simple precipitation tests.

Solubility of salts

Carbonates:

Sodium, potassium and ammonium carbonates are soluble. All other carbonates are

Chlorides:

All chlorides are soluble except for silver and lead chlorides are insoluble.

Nitrates:

All nitrates are soluble.

Sulphates:

All sulphates are soluble except for barium and lead sulphates are insoluble. Calcium sulphate is only slightly soluble.

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