Precipitation of Salt Crystals from Solutions

Problem In demonstrating the precipitation of crystals, it is possible to mix certain solutions the combination of two particular types of ions lead to nearly insoluble salt crystals (see for example Fig. 5.23). In an initial interpretation, one would speak of insoluble salts, they are however usually soluble in very small quantities and are therefore known as slightly soluble - the solubility product will quantitatively provide the limited solubility. Since certain deposits 

Material Test tubes diluted solutions of silver nitrate, sodium chloride, hydrochloric acid, barium chloride, sodium sulfate, sulfuric acid. 

Procedure (a) Mix small volumes of diluted silver nitrate solution with several drops of other solutions listed above, (b) Mix small volumes of barium chloride solution with a few drops of the other solutions listed above. 

Observation (a) A cheesy-white deposit results from silver nitrate solution when hydrochloric acid or chloride solutions are added chloride detection, (b) A crystalline white deposit is left from barium chloride solution when sulfuric acid or sulfate solutions are added sulfate detection. 

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