1 50 CHEMIST R Y FOR A GRIC UL TURAL STUDENTS 



sodium formed. "Aerated bread" is made by mixing the flour with 

 aerated water under pressure. 



Alcohol mixes with water in all proportions. The spirit of 

 wine of commerce is a mixture of alcohol and water. The 

 specific gravity of pure alcohol is .795 at 15.6° C, but that 

 of aqueous alcohol is higher, and varies with the proportion of 

 water ; so that the strength of a spirit can be found by deter- 

 mining the specific gravity. The strength is stated in per- 

 centage of alcohol under or over "proof spirit," i.e. a spirit 

 containing 57 per cent, of alcohol by volume and having a 

 specific gravity of .920. Rectified spirit has a specific gravity 

 of .837, and is 56 per cent, over proof, and therefore contains 

 88.9 per cent, of alcohol. It can obviously be reduced to proof 

 spirit by diluting 100 c.c. to 156 c.c. with water. Perform the 

 experiment, using 50 c.c. of rectified spirit for the purpose. 

 Has the product the specific gravity of proof spirit as deter- 

 mined by the hydrometer ? 



In chemical properties alcohol resembles an inorganic 

 hydroxide, and its formula should therefore be written CgHrjOH, 

 hydroxide of ethyl^ ethyl, CgH^, being an " organic radicle," 

 i.e. a group of elements of which carbon is one that plays the 

 part of a single element. Thus alcohol combines with acids 

 forming "ethereal salts," 



C2H5OH + H2SO4 = C2H5HSO4 4- H,0 

 like KOH -I- H2SO4 = KHSO4 + H2O, 



and when heated with a dehydrating agent loses water and is 

 converted into the ethereal oxide " ether," 



2C2H5OH— H2O = (C2H5)20 

 like 2KOH— H20 = K20. 



To illustrate the formation of an ethereal salt, nitrite of ethyl 

 or nitrous ether, the principal active constituent of sweet spirit 

 of nitre, may be prepared. Dissolve 34.5 grams of sodium 

 nitrite in water, dilute to 120 c.c, pour into a glass cylinder, 



