192 METALS AND THEIR COMBINATIONS. 



Both solutions may now be used for making the respective tests 

 for arsenic or antimony. 



Antidotes. Moist, recently prepared ferric hydrate or dialyzed 

 iron are the best antidotes, insoluble ferric arsenite or arseniate 

 being formed. Vomiting should be induced by tickling the 

 fauces or by administering zinc sulphate, but not tartar emetic. 



QUESTIONS. 



291. Which metals belong to the arsenic group, and what are their 

 characteristics ? 



292. Which non-metallic elements does arsenic resemble? Mention 

 some of the compounds showing this analogy. 



293. How is arsenic obtained in the metallic state; what are its 

 physical and chemical properties ; how does heat act upon it ? 



294. What is white arsenic ? State its composition, mode of manu- 

 facture, appearance, solubility, and other properties. 



295. Which three solutions, containing arsenic, are officinal, and 

 what is their composition ? 



296. How is arsenic acid obtained from arsenious oxide, and which 

 arseniate is officinal ? 



297. State composition and properties of arseniuretted hydrogen, and 

 explain its formation. What use is made of it in testing for arsenic ? 



298. State the composition of realgar, orpiment, Scheele's green, and 

 Schweinfurth green. 



299. Give a detailed description of the process by which arsenic can 

 be detected in organic matter. 



300. Describe Marsh's test and other tests for arsenic, and state the 

 difference between arsenic and antimony spots. 



31. ANTIMONY TIN GOLD PLATINUM MOLYBDENUM. 



Antimony, Sb = 120 (Stibium}. This metal is found in nature 

 chiefly as the trisulphide, Sb 2 S 3 , an ore which is known as bla<-k 

 or crude antimony. 



The metal is obtained from the sulphide by roasting, when it 

 is converted into oxide, which is reduced by charcoal. An- 

 timony is a brittle, bluish-white metal, having a crystalline 

 structure ; it fuses at 450, and may at a higher temperature be 

 distilled without change, provided air is excluded ; heated in 

 air it burns brilliantly. 



