School Science Lessons
Acid-base indicators
2012-02-02 SP
Please send comments to: J.Elfick@uq.edu.au

Table of contents
1.0.0 Acid-base indicators (list): 5.6.2
Indicator pH Range Quantity of indicator per 10 mL Acid Alkali
1.0 Universal indicator
1-14
1 drop 0.1% soln. in water red
violet
1.1 Methyl violet
0.2-3.0
1-2 drops 0.1% soln. in water yellow
violet
1.2 Thymol blue (1st range)
1.2-2.8 1-2 drops 0.1% soln. in water red yellow
1.3 Orange IV (Tropeolin OO)
1.3-3.2 1 drop 1% soln. in water red yellow
1.4 Benzopurpurin 4B
1.2-4.0
1 drop 1% soln. in water in 90% alc. violet
red
1.5 Methyl yellow
2.9-4.0
1 drop 0.1% soln. in water red
yellow
1.6 Methyl orange 3.1-4.4 1 drop 0.1% soln. in water red orange
1.7 Bromophenol blue 3.0-4.6 1 drop 0.1% soln. in water yellow purple
1.8 Congo red 3.0-5.0
1 drop 0.1% soln. in water blue
red
1.9 Bromocresol green 3.8-5.4 1 drop 0.1% soln. in water yellow blue
2.0 Methyl red 4.4-6.3 1 drop 0.1% soln. in water red yellow
2.1 Chlorophenol red
5.4-6.8
1 drop 0.1% soln. in water yellow
red
2.2 Bromcresol purple
5.2-6.8
1 drop 0.1% soln. in water yellow
purple
2.3 Andrade's acid fuchsin
5-8
1 drop 0.1% soln. in water pink
yellow
2.4 Litmus 4.5-8.3
1 drop 0.1% soln. in water red
blue
2.5 Bromothymol blue 6.0-7.6 1 drop 0.1% soln. in water yellow blue
2.6 Phenol red 6.4-8.4 1 drop 0.1% soln. in water yellow red
2.7 Neutral red 6.8-8.0 1 drop 0.1% soln. in 70% alc. red yellow
2.8 Cresol red
7.2-8.8
1 drop 0.1% soln. in water yellow
red
2.9 Thymol blue (2nd range)
8.0-9.6 1-5 drops 0.1% soln. in water yellow blue
3.0 Phenolphthalein
8.2-10.0 1 5 drops 0.1% soln. in 90% alc. colourless red
3.1 Thymolphthalein 9.3-10.5 1 drop 0.1% soln. in 90% alc. colourless blue
3.2 Alizarin yellow R
10.2-12.0 1-5 drops 0.1% soln. in 90% alc. yellow red
3.3 Indigo carmine
11.6-13.0
1 drop 0.1% soln. in 50% ethanol soln. blue
yellow
3.4 Tropeolin 0
11.0-13.0 1 drop 0.1% soln. in water yellow brown-orange
3.5 Nitramine 11.0 13.0 1-2 drops 0.10% soln. in 70% alc. colourless brown-orange
3.6 Trinitrobenzene 12.0-13.4 1 drop 0.1% soln. in water colourless orange