300 



ELEMENTARY GENERAL SCIENCE 



There are thus obtained salts which are known as ammonium 

 salts, viz., ammonium sulphate, &c. 



It will be therefore well to examine the "ammonia liquid," 

 which will be already known to have a very sharp pungent 

 smell, and to colour red litmus blue. 



EXPT. 309. Place some ammonia liquid in a flask and 

 boil, allowing the gas that is evolved to pass over quicklime 

 or solid caustic potash in order to dry it. Collect as shown 

 in the accompanying diagram (Fig. 140). Observe the gas has 

 the same smell as the liquid and 

 similarly acts on red litmus. 



In one jar place a lighted taper. 



Place a second jar in water, and 

 note the rapid absorption of the gas 

 and rise of the water in the jar. 



Dip a rod in hydrochloric acid and 

 hold over a jar of the gas. Ob- 

 serve the formation of white fumes. 



Shake up a jar of the gas with a 

 little water. Examine the solution. 

 See that it is identical with the 

 "ammonia liquid," from which the 

 gas was obtained, and that it loses 

 its odour on boiling, the gas being 

 evolved. 



FIG. 140. Preparation of 

 Ammonium. 



Composition of Ammonia. We 



thus find the "ammonia liquid" is 

 merely a solution of a gas, viz., am- 

 monia, which is very soluble in water, 



which turns red litmus blue, and which does not support 

 combustion, and is apparently not combustible. In an atmo- 

 sphere of oxygen however the gas readily burns, forming nitro- 

 gen and water. It hence contains nitrogen and hydrogen, and 

 may in fact be proved to have the composition represented 

 by NH 3 . To prove this, a long tube is filled with chlorine gas 

 and by means of a funnel and the stopcock some strong liquid 

 ammonia is run into the gas (Fig. 141). Combination ensues 

 between the chlorine and the hydrogen of the ammonia with 

 the formation of white fumes, and frequently a flash of light. 

 The stopcock is then opened under water when the water rises 



