SEPAEATION OF THE METALS OF EACH GROUP. 219 



TABLE VII. Treatment of the precipitate formed by ammonium 



carbonate. 



The precipitate may contain the carbonates Of barium, calcium, and 

 strontium. 1 Dissolve the precipitate in acetic acid, and add potassium chromate. 



1 If an insufficient quantity of ammonium chloride be present, some magnesia 

 may also he precipitated. 



TABLE VIII. Detection of the alkalies and of magnesium. 



The fluid which has been treated with hydrochloric acid, hydrosulphuric acid, 

 ammonium hydrate, sulphide, and carbonate may contain magnesium and the 

 alkalies. 



Divide solution into two portions. 



To the first portion add sodium phosphate. A white crystalline precipitate 

 indicates magnesium. 1 



The second portion is evaporated to dryness, and all ammonium compounds are 

 expelled by heat. The residue is dissolved in water, and platinic chloride added. 

 A yellow precipitate indicates potassium. The residue is also examined by 

 flame-test : a yellow color indicating sodium ; a red color lithium. 



Ammonium compounds have to be tested for in the original fluid by 

 treating it with calcium hydrate, when ammonia gas is liberated. 



1 If an insufficient quantity of ammonium chloride has been produced in the 

 original solution by the addition of hydrochloric acid and ammonium hydrate, a 

 portion of the magnesia may have been precipitated by the ammonium carbonate. 



