Which of the following indicators would be most suitable for the titration of 0.10 M lactic acid with 0.10 M KOH(aq)? For lactic acid, pKa = 3.08.
1. thymol blue (pKIn = 1.7)
2. bromophenol blue (pKIn = 3.9)
3. phenol red (pKIn = 7.9)
4. methyl orange (pKIn = 3.4)
5. alizarin yellow (pKIn = 11.2)