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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: biouoc on November 13, 2010, 10:10:25 AM

Title: precautions to produce (COOH)2 for acidimetry
Post by: biouoc on November 13, 2010, 10:10:25 AM

what are the precautions for producing (cooh)2 for acidimetry and why are the organic acids better than HCl for acidimetry?
 :-\

Title: Re: precautions to produce (COOH)2 for acidimetry
Post by: Borek on November 13, 2010, 10:28:59 AM

Quote from: biouoc on November 13, 2010, 10:10:25 AM

what are the precautions for producing (cooh)2 for acidimetry and why are the organic acids better than HCl for acidimetry?
 :-\

Question as asked doesn't make much sense to me. I don't agree with the statement that organic acids are better than HCl. HCl is a perfect, stable titrant, giving nice, steep inflection on the titration curve; that's not the case with organic acids.

Title: Re: precautions to produce (COOH)2 for acidimetry
Post by: biouoc on November 13, 2010, 10:34:29 AM

i found that question in a book..i found it silly too...they probably mean the exact oposite...what about the first question?it seems so vague to me,that i cannot understand what is required to answer..

Title: Re: precautions to produce (COOH)2 for acidimetry
Post by: Borek on November 13, 2010, 10:40:21 AM

Perhaps they aim at the use of oxalic acid as a standard substance (http://www.titrations.info/titration-standard-substances).

Title: Re: precautions to produce (COOH)2 for acidimetry
Post by: biouoc on November 13, 2010, 10:58:08 AM

yes thank you!! Do you also know how can we explain the ratio 1:1 when EDTA reacts with metal ions? and whats the aim of adding water without ions in the unknown solution in a titration and how can this affect the results in the end?

Title: Re: precautions to produce (COOH)2 for acidimetry
Post by: nimbus on November 17, 2010, 01:57:43 PM

EDTA's 1:1 ratio comes from the chelate effect and gibbs free energy relationships. Look up polydentate in your book.