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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: hardy5086 on April 02, 2016, 03:27:38 AM

Title: enthalpy of solution of oxalic acid
Post by: hardy5086 on April 02, 2016, 03:27:38 AM
I have done a practical trying to determine the enthalpy of solution of oxalic acid. One part of the practical was to determine the concentration of oxalic acid in saturated solutions at different temperatures. I'm not sure my results are correct or not. I would expect that with an increase in temperature the solution would contain more oxalic acid, yet my results are not representative of this. does the solubility of oxalic acid not increase with an increase in temperature?
Title: Re: enthalpy of solution of oxalic acid
Post by: Borek on April 02, 2016, 04:33:33 AM
https://pubchem.ncbi.nlm.nih.gov/compound/oxalic_acid#section=Solubility
Title: Re: enthalpy of solution of oxalic acid
Post by: jeffmoonchop on April 04, 2016, 05:45:02 AM
google oxalic acid solubility curve. Make sure the image you look at is actually oxalic acid. you may need to increase/decrease the temperature by a larger amount if you aren't seeing significant changes.
Title: Re: enthalpy of solution of oxalic acid
Post by: hardy5086 on June 03, 2016, 11:46:22 PM
thanks. I repeated the experiment and got better results.
another quick question. one question that is asked in the lab manual is "Look up the structure of oxalic acid. Examine the structure of the molecule. Are there any uncertainties in how the titration reaction proceeds?"
I'm not exactly sure what they are asking for here. would it be the uncertainty of one acid group reacting with the base but the other not?
Title: Re: enthalpy of solution of oxalic acid
Post by: Borek on June 04, 2016, 03:03:00 AM
That would be my guess - you should check the pKa and the indicator used to make sure whether the end point is after neutralizing one, or two protons.