128 INORGANIC AGENTS 



Derivation. — Made by Leblanc's process. Three steps : 



1st. Salt and sulphuric acid heated together. 2 Na CI + 

 H3 SO, = Na, SO, + 2 HCl. 



2nd. Sodium sulphate is heated with carbon. Na, So, + 

 4 C = Na, S + 4 CO. 



3rd. Sodium sulphide heated with chalk. Na, S + Ca 

 C03 = Na, C03 + Ca S. 



Properties. — Colorless, monoclinic crystals, odorless and 

 having a strongly alkaline taste. In dry air the salt efflor- 

 esces, loses about half its water of crystallization and 

 becomes a white powder. Soluble in 1.6 parts of water and 

 in 1.02 parts of glycerin. Reaction alkaline. 



SoDH Carbonas Exsiccatus. Dried Sodium Carbonate. 

 Na,C03. (U. S. & B. P.) 



Synonym. — Natrum carbonicum siccum, P. G.; carbo- 

 nate de soude, Fr.; getrocknete soda, G. 



Derivation. — Sodium carbonate (200 gm.) is broken into 

 'small fragments and allowed to effloresce in dry air. It is 

 then heated to drive off water of crystallization, till it weighs- 

 100 Gm. 



Properties. — A loose, white powder, corresponding in 

 solubility to sodium carbonate. Reaction alkaline. Action 

 of sodium carbonate similar to the hydrate, but infrequently 

 employed in medicine. 



Dose.—B.. & C, 3ii.-vi. (8.-24.); Sh. & Sw., gr.xx.-xl. 

 (1.3-2.6); D., gr.v.-xx. (.3-1.3). Given in large amount of 

 water. 



SoDH BiCARBONAS. Sodium Bicarbonate. Na HCO3. 

 (U. S. & B. P.) 



Synonym,. — Soda, baking soda, sodium sesquicarbonate, 

 natrum carbonicum acidulum, bicarbonas sodicus, sodium 

 hydrocarbonate, bicarbonate of soda, E.; natrum bi carboni- 

 cum, P. G.; bicarbonate de soude, sel digestive de vichy, Fr.; 

 doppelkohlensaures natron, G. 



