86 ^ Examination of the Peroxide of Manganese. 



Chromic acid. — Chromic acid seems to have no action upon 

 the peroxide, but a chromate may be formed by digesting the 

 peroxalate in chromic acid. The solution is of a dark chestnut 

 brown, but it cannot be evaporated or crystallized, as it is decom- 

 posed by the application of heat. 



Bichromate of potassa has no action upon the deutoxide of 

 manganese. 



Oxalic acid. — This acid has a violent effect upon the perox- 

 ide. Oxygen is given off, the insoluble protoxalate is precipita- 

 ted, while a soluble peroxalate remains in solution. By careful 

 evaporation it may be crystallized, but it is very apt to be de- 

 composed, forming an insoluble salt, most probably the protoxa- 

 late. It dissolves in muriatic and nitric acid. It was analyzed 

 by dissolving and precipitating the oxalic acid by chloride of cal- 

 cium ; while another portion was calcined and converted into 

 manganoso-manganic oxide. Treated in this manner it showed 

 27.4348 per cent, of oxalic acid, and 8.5 of manganoso-manganic 

 oxide =11.73 of peroxide. This leaves a very large per centage 

 for water of crystallization. Thus 



Oxalic acid, - - - - - 27.4348 

 Peroxide of manganese, - - - 11.7300 

 Water and loss, - - - _ 60.8352 



100.0000 



The 11.73 of oxide, requires very nearly 16. of oxalic acid; 

 which leaves 11.4348 of free acid, so that this salt, in common 

 with the others, possesses a great excess of acid. 



If binoxalate of potassa be digested upon the deutoxide of man- 

 ganese, in the cold, a pink colored solution is formed, which by 

 standing becomes yellow, letting fall a pink powder. If the so- 

 lution of the binoxalate be hot, the action is very violent, and 

 the resulting solution is yellow. By evaporation it leaves a crys- 

 talline, almost tasteless mass, partly white and partly green, and 

 which is readily dissolved in water. 



Acetic acid. — Glacial acetic acid does not form a per-salt when 

 digested on peroxide of manganese. 



Tartaric acid. — If this acid be digested upon peroxide, oxy- 

 gen is given off and the prototartrate is formed. But if we dis- 

 solve deutoxide instead of peroxide, a pertartrate results, which 

 on being evaporated leaves the salt of a light yellow or straw 

 color. 



