Concentation of Citric Acid in Fruit Juice

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Discussion Overview

The discussion revolves around the concentration of citric acid in fruit juice, specifically focusing on a lab experiment involving the titration of Tang juice with sodium hydroxide. Participants explore the chemical reactions involved, the balanced equation for the reaction, and the implications for calculating the concentration of citric acid.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant provides the initial setup for a titration experiment and seeks help with the balanced chemical equation for the reaction between citric acid and sodium hydroxide.
  • Another participant suggests that the user is on the right track and shares a link for titration calculations.
  • A different participant proposes a balanced equation involving sodium hydroxide and citric acid but expresses confusion about the formation of sodium as a product.
  • Some participants challenge the proposed equation, asserting that the product is a sodium salt rather than elemental sodium.
  • There is a clarification that a salt in chemistry refers to an ionic compound formed from the neutralization of an acid and a base, and that the correct representation of the product involves ions rather than solid sodium.
  • Another participant identifies the product of the reaction as sodium citrate, further clarifying the nature of the resulting compound.

Areas of Agreement / Disagreement

Participants express differing views on the balanced equation and the nature of the products formed in the reaction. There is no consensus on the correct representation of the chemical reaction, and confusion remains regarding the role of sodium in the products.

Contextual Notes

Participants have not reached a resolution on the balanced equation, and there are unresolved questions about the nature of the products formed during the titration.

Gurvir
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Homework Statement


This is a lab for Chemistry in grade 12.

I'll give some basic info I have.

Juice substance is Tang.
A solution of juice is prepared by dissolving 4.00 grams of crystals in 100.0 mL of solution. The juice solution is then titrated using a given solution of sodium hydroxide. Phenolphthalein is used as an indicator.

Here is my observations,

Trial # NaOH(aq) added (mL)
Trial 1 3.31
Trial 2 3.18
Trial 3 3.27

Homework Equations


a) find mol/L of acid (I can do this but I cannot figure out the balanced equation)
b) how many grams of pure citric acid is in 100 g of tang (as a percent mass)
*Citric Acid is in your databook. Assume it loses 3 hydrogens.
My teacher said you shouldn't need the formula of the Tang

The Attempt at a Solution



This is all I can think of, I do not know what it will turn into.

C3H5O(COOH)3(aq) + NaOH(aq) ==>
 
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Borek said:
You are on the right track.

http://www.titrations.info/titration-calculation

I think I understand it more now!

Let me see,

C3H5O(COOH)3(aq) + 3 NaOH(aq) ==> C3H5O(COO)3(aq) + 3 H2O(l) + 3 Na(s)

But there wasn't any solid from the reaction so I'm not sure where the Na(s) goes, does it just separate or get added onto one for the formula's?
 
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No no, that was completely wrong. Your product will be a sodium salt!
 
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Borek said:
No no, that was completely wrong. Your product will be a sodium salt!

--
buffer calculator, concentration calculator
pH calculator, stoichiometry calculator

What? Now I'm confused again, how does that work? Please tell me asap, I don't have long until I have to have this lab complete.

Why would it be NaCl? That doesn't make sense with anything. Cl wasn't even part of the experiment. It can't be created through thin air.

C3H5O(COOH)3(aq) + 3 NaOH(aq) ==> C3H5O(COO)3(aq) + 3 H2O(l) + 3 Na(s)

This makes sense to me, I don't know where NaCl would go.
 
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A salt in chemistry isn't necessarily table salt (NaCl) but an ionic compound you get, along with water, after the neutralization of an acid and [STRIKE]salt[/STRIKE] base.

You wouldn't actually have C3H5O(COO)3(aq) and Na(s), but rather C3H5O(COO)33-(aq) and Na+(aq). The first one ionized since it lost H+ ions while the Na is still an Na+ ion. It could also be written as Na3C3H5O(COO)3(aq)
 
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Bohrok already nicely explained what is going on. Salt name is sodium citrate.
 
Last edited by a moderator:

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