LIST OF REAGENTS 



617 



Alizarin red. 

 Cochineal tincture. 



Congo red. 

 Litmus. 



Methyl orange. 

 Methyl violet. 

 Phenolphthalein. 



INDICATORS. 



i o gm. sodium alizarin sulphonate are dissolved in water 

 and made up to i litre = i per cent. 



5 gm. cochineal are extracted with 150 c.c. alcohol + 

 100 cc. water for several days ; the solution is then 

 filtered. 



i gm. congo red is dissolved in water and made up to 

 i litre = 0*1 per cent. 



10 gm. litmus are finely powdered and extracted with 

 50 cc. hot water. The blue liquid is decanted and 

 made up to i litre = i per cent. 



i gm. methyl orange is dissolved in 500 c.c. alcohol and 

 made up to i litre with water = 0*1 per cent. 



i gm. methyl violet is dissolved in water and made up to 

 i litre =a 0*1 per cent. 



10 gm. phenolphthalein are dissolved in alcohol and 

 made up to i litre with alcohol = i per cent 



