208] REAGENTS FOR THE ACID-RADICALS 



83 



J. — Reagents for General Use for the Detection of 

 Acid-radicals 



* These solids do not keep in solution. 



Note 1. — The solution should not contain any free acid. To remove 

 this AmHO is added until the further addition of a single drop gives 

 a reddish-brown precipitate. Filter off this precipitate, and the solu- 

 tion is ready for use. 



Note 2. — Should be kept in fine powder ; it must not evolve CI or 

 C0 2 when warmed with strong H 2 S0 4 . 



Note 3. — See note 2, paragraph 266. 



N te 4.— Dry finely powdered Na 2 CO a and K 2 CO s are mixed in 

 proportions of 53 : 69 by weight and kept in a stoppered bottle. 



Mote 5.— Dissolve 20 grams NaA in 60 c.c. of distilled water and 

 add to the solution 40 c.c.of strong HA. 



