STAINING, PRACTICAL AND THEORETICAL 



PHENOLPHTHALEIN 



pH 8-2-IO-0 



Phenolphthalein . . . . , . . . i gm. 



Alcohol 70% . . . . . , . . 100 ml. 



PHENOL RED 



pH 6-6-8-4 



Phenol red . . . . . . . . . . 0-04 gm. 



N/iooNaOH 11-36 ml. 



Distilled water .. .. .. .. 68-64 ml. 



Absolute alcohol . . . . . . . . 20 ml. 



ROSOLIC ACID 



pH 6-8-8-2 



Rosolic acid 

 Alcohol 50% 



THYMOL BLUE 



pH 1-2-2-8 and 8-0-9-6 



Thymol blue 

 N/iooNaOH 

 Distilled water 

 Absolute alcohol 



0-5 gm. 

 100 ml. 



0-04 gm. 

 8-6 ml. 

 71-4 ml. 

 20 ml. 



THYMOLPHTHALEIN 



pH 9-3-10-5 



Thymolphthalein . . . . . . . . o-i gm. 



Alcohol 50% . . . . . . . . 100 ml. 



UNIVERSAL INDICATOR 



pH i-o-io-o 



Universal indicator powder .. .. o-i gm. 



Alcohol 70% . . . . . . . . 100 ml. 



or 



I Universal indicator tablet dissolved in 



10 ml. of 70% alcohol 



Note: A comparator is not required with Michrome universal indicator, as 

 it gives very definite colour changes as follows : 



pH I cherry red pH 2 rose pH 3 red-orange 



pH 4 orange red pH 5 orange pH 6 yellow 



pH 7 yellow-green pH 8 green pH 9 blue-green 

 pH 10 blue 



544 



