Titration with Carbonates acting as bases

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    Bases Titration
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Discussion Overview

The discussion revolves around the effects of carbon dioxide formation during the titration of carbonates acting as bases with acids, specifically focusing on how carbonic acid formation can influence the titre value. Participants explore methods to mitigate the impact of dissolved CO2 on the titration results.

Discussion Character

  • Homework-related
  • Debate/contested
  • Exploratory

Main Points Raised

  • One participant suggests that heating the titration flask may help remove dissolved CO2, as increased temperature decreases gas solubility.
  • Another participant proposes adding more sodium carbonate (Na2CO3) to eliminate CO2, but this is challenged as it could skew the results since the amount of carbonate is unknown.
  • A later reply supports the heating method and introduces alternative methods such as sparging or vacuum degassing to remove CO2.
  • Participants express a need for clarification on why adding more carbonate is not a viable solution in the context of titrating an unknown amount.

Areas of Agreement / Disagreement

There is no consensus on the best method to address the issue of CO2 affecting the titration results. While heating is generally supported, the effectiveness of adding more carbonate is contested.

Contextual Notes

Participants highlight the dependence on the unknown quantity of carbonate in the titration, which complicates the addition of more carbonate as a solution. The discussion also reflects uncertainty regarding the equilibrium dynamics involved.

Who May Find This Useful

This discussion may be useful for students or individuals interested in analytical chemistry, particularly those studying titration techniques and the effects of gas solubility on chemical reactions.

Kushal
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Homework Statement



when a carbonate acts as a base and neutralises an acid, CO2 is formed. the problem is that some of the CO2 dissolves in the water and forms Carbonic Acid.the Carbonic acid will affect the titre value as it will react with the base, along with the HCl. How do we prevent this to happen?


Homework Equations



Na2CO3 + HCl -----> 2NaCl + CO2 + H2O

CO2 + H2O ------> H2CO3


The Attempt at a Solution



what I'm thinking of is that, by heating the flask containing the titrating mixture as the titration is performed, the CO2 may dissolve out of the water...

Is it a good solution? If you have any other suggestion, let me know,
 
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Is there any way that you could think of that could throw off the equlibrium?
 
Stevedye56 said:
Is there any way that you could think of that could throw off the equlibrium?

Yeah, you're right; i can eliminate the CO2 by just added a lil' bit more of the Na2CO3...

thnx...

but the heat thing also works perfect, since solubility of a gas decreases with increase in temperature.
 
Kushal said:
Yeah, you're right; i can eliminate the CO2 by just added a lil' bit more of the Na2CO3...

This won't work. You are titrating an unknown amount of carbonate with an acid. Adding additional carbonate will skew your results.

The heating idea is good. Sparging or vacuum degassing also works.
 
Heating is probably your best bet. It will be the simplest for you unelss you are just doing the problem for homework. Then you could just mention the various ways.
 
hey chemisttree can you explain to me in more detail why the saturation of the solution with the carbonate won't work...
 
Kushal said:
hey chemisttree can you explain to me in more detail why the saturation of the solution with the carbonate won't work...

Well, you ARE trying to titrate an unknown amount of carbonate. How will adding additional carbonate help you with that?
 

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