8 § 1. KEAGENTS. 



1. a.— Acid, acetic— HC,H30.,. (HO,C,H303. HO, A.) 



— This should leave no residue on evaporation, and 

 should emit no empyreumatic odor when evaporated after 

 saturation with sodic carbonate ; neither hydrosulphuric 

 acid, argentic nitrate, nor baric chloride should produce 

 any change in it, nor amnionic sul23hide, after neutraliza- 

 tion with ammonia. 



h. Acid, Citric— H^CJI.O,. (3H0,C,,H,0,^.)— ^ecrys- 

 tallize it, unless clean and colorless. 



c. Acid, hydrocllloric — HCl. (Chlorhydricacid. Mu 

 riatic acid.) — This must be colorless, and it should leave 

 no residue when evaporated on platinum foil, nor should 

 it attack the foil ; it should give no blue color to starch- 

 paper, nor should it bleach starch that has been faintly 

 colored blue with iodine ; it should give no turbidity with 

 baric chloride, after having been considerably diluted, nor 

 should it be colored by hydrosulphuric acid or potassic 

 sulphocyanate. 



For the dilute acid, add the concentrated acid to 4 parts 

 of water. 



d. Acid, hydrosulpliuric — H^S. (HS.)— Pour dilute 

 sulphuric acid through a funnel tube over fused ferrous 

 sulphide, in a common bottle, and conduct the gas that is 

 evolved, first through water in a small wash-bottle, and 

 then into distilled Avater. The solution should emit a 

 strong odor of sulphuretted hydrogen, and should be 

 freshly made. 



e. Acid, nitric— HNO3. (HO,NO,.)— This should be 

 colorless, and should leave no residue w^hen evaporated on 

 platinum foil ; after having been considerably diluted, it 

 should not be made turbid by argentic nitrate or baric 

 chloride. For the dilute acid, add the concentrated acid 

 to 4 parts of water. 



/. Acid, nitro-hydrocliloric Aqua regia.— Mix to- 

 gether 1 part of pure nitric acid, and 3 or 4 parts of pure 

 hydrochloric acid. 



