BISMUTH. 171 



by adding sodium carbonate to solution of bismuth nitrate, 

 when the subcarbonate is precipitated, some carbon dioxide 

 escaping : 



2(Bi3N0 3 ) + 3Na 2 C0 3 + H 2 O = 6NaNO 3 + 2CO 2 + (BiO) 2 CO 3 .H 2 O. 



A white, or pale yellowish-white powder, resembling the sub- 

 nitrate. It readily loses water and carbon dioxide on heating, 

 while the yellow oxide, Bi 2 3 , is left. 



Analytical reactions. 



1. Add to solution of bismuth, hydrosulphuric acid or ammo- 

 nium sulphide: a dark brown (almost black) precipitate of bis- 

 muth sulphide, Bi 2 S 3 , is produced : 



2BiCl 3 + 3H 2 S = 6HC1 + Bi 2 S 3 . 



2. Pour a previously concentrated acid solution of bismuth 

 into water: a white precipitate of a bismuthyl salt is formed. 

 (See explanation above.) 



3. Add to bismuth solution ammonium or sodium hydrate, 

 or carbonate : a white precipitate of bismuth hydrate, Bi3HO, 

 or of bismuthyl carbonate is produced. (See explanation 

 above.) 



QUESTIONS. 



271. What are the properties of lead, and from what ore is it ob- 

 tained? 



272. What is litharge, and how does it differ from red lead ? 



273. Give the composition of nitrate, carbonate, and iodide of lead ; 

 how are they made ? 



274. State the analytical reactions for lead. 



275. How is copper found in nature? 



276. How many oxides of copper are known ; what is their com- 

 position and under what circumstances are they formed ? 



277. What is " blue vitriol ;" how is it made, and what are its 

 properties ? 



278. How does ammonium hydrate act on cupric solutions? 



279. Mention tests for copper. 



280. What is the composition of subnitrate and subcarbonate of 

 bismuth; how are they made from metallic bismuth, and what explana- 

 tion is given in regard to their constitution ? 



