INDICATOR |
pH RANGE |
QUANTITY OF INDICATOR PER 10 mL |
ACID |
ALKALINE |
Thymol blue (A)*† |
1.2-2.8 |
1-2 drop of of 0.1% solution in aq. |
Red |
Yellow |
Methyl orange (B) |
3.1-4.4 |
1 drop of 0.1% solution in aq. |
Red |
Orange |
Bromphenol blue (A)† |
3.0-4.6 |
1 drop of 0.1% solution in aq. |
Yellow |
Blue-Violet |
Bromphenol green (A)† |
4.0-5.6 |
1 drop of 0.1% solution in aq. |
Yellow |
Blue |
Methyl red (A)† |
4.4-6.2 |
1 drop of 0.1% solution in aq. |
Red |
Yellow |
Bromcresol purple (A)† |
5.2-6.8 |
1 drop of 0.1% solution in aq. |
Yellow |
Purple |
Bromthymol blue (A)† |
6.2-7.6 |
1 drop of 0.1% solution in aq. |
Yellow |
Blue |
Phenol red (A)† |
6.4-8.0 |
1 drop of 0.1% solution in aq. |
Yellow |
Red |
Neutral red (B) |
6.8-8.0 |
1 drop of 0.1% solution in 70% alc. |
Red |
Yellow |
Thymol blue (A)†‡ |
8.0-9.6 |
1-5drops of 0.1% solution in aq. |
Yellow |
Blue |
Phenolphthalein (A) |
8.0-10.0 |
1-5 drops of 0.1% solution in 70% alc. |
Colorless |
Red |
Thymolphthalein (A) |
9.4-10.6 |
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.