LIST OF REAGENTS 



615 



Mercuric nitrate. 

 Milton's reagent. 



a-Naphthol solution. 

 Nessler's reagent. 



Nylanders solution. 

 Obermayer" s reagent. 



Oil of turpentine . 



Oxalic add solution 

 (sat.}. 



Pavy's sohition. 



Phenol solution. 



Phosphotungstic acid 

 solution. 



Picric acid solution 

 (sat.). 



10 gm. mercuric nitrate are dissolved in water and made 

 up to i litre. 



400 gm. mercury ( = 30 c.c.) are dissolved in 570 c.c. 

 cone, nitric acid. The solution is then diluted 

 with two volumes of water. 



144 gm. a-naphthol are dissolved in alcohol and made 

 up to i litre with alcohol. 



62 '5 gm. of potassium iodide are dissolved in 250 c.c. 

 of distilled water. A few c.c. of this solution are 

 set aside. To the remainder is added a cold 

 saturated solution of mercuric chloride (about 

 500 c.c.) until the precipitate of mercuric iodide 

 no longer dissolves on stirring. As soon as a 

 permanent precipitate results the few c.c. which 

 were removed are added so as to dissolve the 

 precipitate. Mercuric chloride is again added very 

 gradually until a slight permanent precipitate is 

 formed. A cold solution of 150 gm. of potassium 

 hydrate dissolved in 150 c.c. of water is slowly 

 added and the volume is made up to 1000 c.c. 

 A brown precipitate settles and a pale greenish- 

 yellow solution is obtained. It is decanted into 

 a smaller vessel before use. 



This reagent is diluted with 5 volumes of water before 

 adding it to the ammonia solution so as to avoid 

 a turbidity. One-third of the quantity should 

 be added at a time. 



5 c.c. of the reagent diluted with 25 c.c. of water are 

 required for i mgm. of nitrogen in the ammonia 

 solutions. 



40 gm. Rochelle salt 'I are dissolved in 1000 c.c. 



20 gm. bismuth subnitrate/ caustic soda (8 per cent.). 



4 gm. ferric chloride are dissolved in i litre cone, hydro- 

 chloric acid. 



Commercial. 



100 gm. oxalic acid are dissolved in i litre of water. 



120 c.c. Fehling's solution \are made up to i litre 

 300 c.c. ammonia (sp. gr. -88o)J with water. 



20 gm. carbolic acid are dissolved in i litre of water. 



50 gm. phosphotungstic acid^are dissolved in water and 

 30 c.c. cone, sulphuric acid J made up to i litre. 



1 2 gm. picric acid are dissolved in water and made up 

 to i litre. 



