Dear all,
For measuring the titratable acidity, I see titration of sample with 0.1 N NaOH to reach specific pH and reported by lactic acid. But the specifi pH I see is different in literiture, which one I should choose? does pH depends on the type of sample we have? For example I see pH is 6.6 or 8.5 or 7.4. I am confused ed please let me know your guidance. Thank you.
Also, is ''titratable acidity'' the same as ''total titratable acidity''? thanks
Weigh accurately 3 g of Lactic Acid, add 40 ml of 1 N sodium hydroxide solution, heat in a water bath for 10 minutes, and titrate the excess alkali with 1 N sulfuric acid while hot (indicator
: 1～2 drops of phenolphthalein solution).
Perform a blank test in the same manner.
1 N sodium hydroxide 1 ml = 90.08 mg of C3H603
In general., you can titrate with sodium hydroxide but the calculations are different for each acid:
Itaconic acid: 0.1 N sodium hydroxide solution 1 ml ＝ 6.505 mg C5H6O4;
Lactic acid: 1 N sodium hydroxide 1 ml = 90.08 mg of C3H603;
Citric acid: 0.1 N sodium hydroxide 1 ml ＝ 6.404 mg C6H8O7;
Etc.
Always in the presence of the indicator 2～3
drops of phenolphthalein solution.
Dear Nikolay,
Thank you very much for your answer and guidance, my question is what is the pH at which we stop titration? Because I see in literature they mention different pH like 6.6, 7.4.... so I am wondering why its different and if its depending on the type of sample? Thank you very much
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