Weak acid such as acetic acid can dissolve in water and also other organic solvents. During dissolution of acetic acid in water, some of the molecules will dissociates or ionized into CH3COO- and H+. This phenomenon can increase the electrical conductivity of the system. My question is it possible for acetic acid to show the same behaviour in other organic solvent such as ethyl acetate? Ethyl acetate is a polar aprotic solvent with low dielectric constant.
Yes, polar solvents will produce the same effect as water, although with a lower extent. For instance, using acetic acid in methanol, you can measure the pH and see that it is far below 7. Despite such measurement is worng, it shows that the solution is acidic.
Alain
Ok. Thank you very much. I guess during the dissolution process, some the acetic acid molecules will dissociates and become CH3COO- and H+, while some some of will remain as molecule. What about methanol and ethyl acetate? Are the going to dissociate as well? For water, the molecule can self-ionize becoming H3O+ and HO-.
Yes, the dissociation of weak acids occurs with polar solvents, but only partly, as in water. However, the corresponding equilibrium constant has not the same value as in water.
Alain
With regards to the subject of your question, you may refer to section 4-10 entitled "pH measurements in nonaqueous solvents" at: Herbert A. Laitinen & Walter E. Harris, “Chemical Analysis ─ An Advanced Text and Reference”, 2nd ed., McGraw-Hill Kogakusha, 1975, pp. 85-88 & 94.
thank you very much for the answers. I will find the book as well.
P.S. Elsewhere at this forum I have suggested a solution of acetic acid in ethyl acetate as a promising solvent for the acid extraction of some natural alkaloids: https://www.researchgate.net/post/What_acid_is_useful_for_extraction_of_alkaloids
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