I did a lab on vinegar and titration. The question asks..
In the titration of acetic acid and NaOH the use of the color indicator mandates that excess base be present to detect the reading endpoint. Will this cause the calculated and reported mass percent of acetic acid in vinegar to be too high or too low? Explain.
I understand that in order to see an endpoint there must be somewhat excess of base I am just confused on whether or not it'll be too low or high. I was thinking too low. But I'm not sure, help??
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In actual practice you try to set these things up so that the amount of excess added is such a small amount (0.01-0.03 mL) that it doesn't affect the results AND if you run a blank at the same time that usually takes care of that problem. Technically, however, you must add a small excess. So mols added extra is M x L = mols NaOH. That translates to mols acetic acid extra and that means SLIGHTLY higher results in grams and percent. Usually that's not anything to get too excited about.
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