# Brown color at end point during titration with phenolphthalein as indicator

We did a titration experiment at school and I did not understand one part of it.

The scenario:

• Titrate : White wine (ethanoic acid)
• Titrant: $\ce{NaOH}$
• Indicator: Phenolphthalein

What happened: We carried out the titration and the end point was a brown colour!

How does that happen? Why is the color brown and not pink?

• I strongly recommend AGAINST closure of this question. It may have come from a school demonstration, but it's a curious observation. Why indeed would phenolphthalein turn brown instead of pink? A Google search yields no obvious explanation, and brown appears nowhere on the phenolphthalein Wikipedia page. – hBy2Py Apr 4 '16 at 13:26
• I don't think this can be untangled. (1) There shouldn't be acetic acid in white wine. (2) When titrating did the solution turn pink where the drops of NaOH went into the solution? (3) I assume that the color of the "wine" was yellow. What happens if you titrate with NaOH using no phenolphthalein? – MaxW Apr 4 '16 at 17:52
• I went looking for a titration of apple cider vinegar (which would be yellow) with NaOH and phenolphthalein on youtube but didn't find one. It could be that the yellow plus pink gives some sort of "dirty orange" that looks brownish right at the end point. – MaxW Apr 4 '16 at 18:17
• @MaxW "I don't think this can be untangled." Certainly possible, with how complex a solution the white wine is. Still, worth keeping open, I think. – hBy2Py Apr 5 '16 at 18:15