Exploring Solvents for ASA: Why Not Ether or Chloroform?

[kevin935]

Homework Statement

I am trying to help my son with his experiment with asa(aspirin). He titrated asa powder that was dissolved in isopropyl alcohol with NaOH. One of the questions in the inquiry was why were ether or chloroform not used to dissolve the asa? I am not certain that the answer is related to the volatility of both ether and choloroform, relative to isopropyl alcohol, or due to the fact that the alcohol is a protic solvent rather than an aprotic solvent. Any suggestions??

Homework Equations

The Attempt at a Solution

 

[GCT]

What is the scope of the experiment? Otherwise I am soley able to claim that it's solubility that is being referred to here. An aqueous solution of NaOH is not going to dissolve in either of those other solvents from what I know.

 

[Blueshift5]

There are a few reasons why ether and chloroform may not be suitable solvents for dissolving ASA. First, as you mentioned, both ether and chloroform are highly volatile solvents which can be hazardous to work with. Additionally, they are both flammable, which could pose a safety risk during the experiment.

Another factor to consider is the polarity of the solvents. ASA is a polar compound, meaning it has a positive and negative end. In order to dissolve it, a polar solvent is needed. Isopropyl alcohol is a polar solvent, while ether and chloroform are nonpolar solvents. This means they may not be able to effectively dissolve the ASA, resulting in inaccurate titration results.

Furthermore, as you mentioned, isopropyl alcohol is a protic solvent, meaning it has a hydrogen atom that can form hydrogen bonds with the ASA molecules. This allows for better solvation of the ASA and helps to stabilize it in solution. Ether and chloroform are aprotic solvents, meaning they do not have a hydrogen atom available for hydrogen bonding. This could also contribute to the difficulty in dissolving the ASA in these solvents.

In conclusion, the choice of isopropyl alcohol as a solvent for dissolving ASA is likely due to a combination of factors, including safety, polarity, and the ability to form hydrogen bonds. I hope this helps to clarify the reasons behind the choice of solvent in your son's experiment.