The hydroxides of the hydrocarbon radicles are, as mentioned on p. 67, termed alcohols.¹ Of these there are very many, but a few only will be chosen to serve as examples: methyl alcohol, CH₃OH, ethyl alcohol, CH₃-CH₂OH, as types of monohydric alcohols, which may be taken as the analogues of the hydroxides of the monad metals; glycol, , a dihydric alcohol, may be likened to barium hydroxide,

¹ A special class of such hydroxides derived from benzene, C₆H₆, are termed phenols. ¹¹ Carbolic acid," C₆H₅OH, is the best known of these.

Ba(OH)₂; and glycerine (glycerol), is a trihydric alcohol, as aluminium hydroxide is a trihydroxide. These substances differ from the hydroxides, however, by their being non-electrolytes, and therefore non-ionised. Or perhaps it is more correct to say that their conductivity is of the same order of magnitude, but less in value, than that of pure water. The corresponding halides, for example, CH₃C1, C₂H₄C1₂, and C₃H₅C1₃, are also regarded as non-ionised ; they are practically insoluble in water. Nevertheless, methyl chloride has been transformed into methyl alcohol by heating with water to a high temperature in a sealed tube under pressure-CH₃C1 + HOH = CH₃OH + HC1; and the others, but preferably the bromides, may be similarly changed into hydroxides by heating with silver hvdroxide. or with silver oxide and water :

Is it possible that at a higher temperature the ionisation is sufficient (though it must be exceedingly small) to produce the interaction ?

The metals sodium and potassium dissolve in the alcohols, with evolution of hydrogen, forming compounds somewhat analogous to the hydroxides ; instead of hydrogen, however, they contain a hydrocarbon group : sodium methoxide, for example, has the formula Na(OCH₃). Such substances are white solids, like caustic soda.