Halides, alkyl from inorganic esters

Strictly speaking the alkyl halides are esters of the halogen acids, but since they enter into many reactions (t.g., formation of Grignard reagents, reaction with potassium cyanide to yield nitriles, etc.) which cannot be brought about by the other eaters, the alkyl halides are usually distinguished from the esters of the other inorganic acids. The preparation of a number of these is described below. 

The esters of a number of inorganic acids are known. Those derived from the strong acids may be prepared directly from the acid and alcohol. In the case of the weak acids the esters can be prepared as the result of the interaction of the silver salt of the acid with an alkyl halide for example, ethyl sulphite may be made by the reaction expressed by the equation,... 

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