INDICATOR 
pH RANGE 
QUANTITY OF INDICATOR PER 10 mL 
ACID 
ALKALINE 

Thymol blue (A)*† 
1.22.8 
12 drop of of 0.1% solution in aq. 
Red 
Yellow 

Methyl orange (B) 
3.14.4 
1 drop of 0.1% solution in aq. 
Red 
Orange 

Bromphenol blue (A)† 
3.04.6 
1 drop of 0.1% solution in aq. 
Yellow 
BlueViolet 

Bromphenol green (A)† 
4.05.6 
1 drop of 0.1% solution in aq. 
Yellow 
Blue 

Methyl red (A)† 
4.46.2 
1 drop of 0.1% solution in aq. 
Red 
Yellow 

Bromcresol purple (A)† 
5.26.8 
1 drop of 0.1% solution in aq. 
Yellow 
Purple 

Bromthymol blue (A)† 
6.27.6 
1 drop of 0.1% solution in aq. 
Yellow 
Blue 

Phenol red (A)† 
6.48.0 
1 drop of 0.1% solution in aq. 
Yellow 
Red 

Neutral red (B) 
6.88.0 
1 drop of 0.1% solution in 70% alc. 
Red 
Yellow 

Thymol blue (A)†‡ 
8.09.6 
15drops of 0.1% solution in aq. 
Yellow 
Blue 

Phenolphthalein (A) 
8.010.0 
15 drops of 0.1% solution in 70% alc. 
Colorless 
Red 

Thymolphthalein (A) 
9.410.6 
1drop of 0.1% solution in 90% alc 
Colorless 
Blue 
A: Indicator of acid * For the acid range. B: Indicator of base ‡ For the alkaline range. † Sodium salt.