Sodium, Dried Sulphate of. Syn. Sodæ sulphas exsiccata, Effloresced Glauber salt. Expose the crystals to a warm dry air till they fall into powder. They lose half their weight. The dose is reduced in like proportion.
Sodium, Effervescing Citro-tartrate of. Syn. Sodæ citro-tartras effervescens. (B. P.) Prep. Mix thoroughly, powdered bicarbonate of soda, 17 oz.; tartaric acid, 8 oz.; and citric acid, 6 oz.; place in a dish or pan of suitable form, heated to between 200° and 220° Fahr., and when the particles begin to aggregate, stir assiduously till they assume a granular form. By means of suitable sieves separate the granules of uniform and most convenient size. Preserve in well-closed bottles.
Sodium, Ethylate. Prepared as Potassium ethylate, substituting sodium for potassium. Properties similar to ethylate of potassium.
Sodium, Hydrate of. NaHO. Syn. Hydrate of soda, Sodium hydrate, Caustic soda; Sodæ hydras. Prep. Exactly in the same manner from carbonate of sodium as potassium hydrate is prepared from carbonate of potassium.
The ‘Pharmaceutical Journal’[177] states that
a pure hydrate of sodium is now manufactured from metallic sodium by the following method:—A deep silver vessel, of a hemispherical form, and capable of holding about four gallons of water, is employed. Into this vessel, which is cooled externally with a current of cold water, is placed a very little water, and upon the water is placed a cube of metallic sodium, of about half an inch in diameter.
[177] 3rd series, i, 65.
The vessel is made to revolve, so as continually to bring fresh portions of liquid into contact with the metal, and by this means explosion is avoided. When the first cube of metal has dissolved, and yielded a thick syrupy liquid, a little more water and a second cube of metal are added, and the reaction allowed to take place, as before, the vessel being kept in motion all the time. In this manner several pounds of sodium may be worked up into soda.
The thick syrup so resulting is next evaporated down, heated to redness, fused, and poured into a mould.
Inasmuch as the price of sodium is five shillings a pound, the yield of soda from 1 lb. of metal being about 13⁄4 lb., it is plain that the alkali so prepared must be cheap.