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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: Wil" on April 15, 2007, 03:54:53 AM

Title: titration on citric acid of the orange juice
Post by: Wil" on April 15, 2007, 03:54:53 AM

I'm going to do a titration on citric acid which is titrated against NaOH. I have these questions which drive me crazy~~~
1. Concerning the molarity of NaOH being used, is the molarity dependent on the amount of citric acid used?? Or any concentration will do??
2. How about the volume of orange juice being titrated??
3. Do I need to dilute the orange juice first??

Please help me!!

Title: Re: titration on citric acid of the orange juice
Post by: Dolphinsiu on April 16, 2007, 06:54:10 AM

1. NaOH + HA --> NaA + H2O

Do you think the above equation can answer your question?

2. Just take an average on your titration results (no. of citric acid added for reaching the end pt if methyl orange is used, color will change from orange to yellow. if phenolphthalein is used as indicator, color will change from purple (deep pink) to colorless)

3. In normal cases, you no need to dilute as citric acid is weak acid and NaOH is strong base. The steapest proportion on titration curve lies near above 7, so phenolphthalein is a best indicator to be used.