Respuesta :
Answer: maybe you need to do very dilute solution?
Explanation: you should have an pH meter instead of indicator.
Phosphoric acid H3PO4 have three ekvivalent points.
Another way could be using a conductivity meter.
For dark reactants, use a pH meter.
For colorless WEAK reactants(acids/bases), use phenolpthalein..
For colorless STRONG reactants, use methyl orange.
For colorless WEAK reactants(acids/bases), use phenolpthalein..
For colorless STRONG reactants, use methyl orange.