Carboxylate: Difference between revisions

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:[[File:Carboxylate-resonance-2D.png|400px|Equivalence of the resonance forms the delocalised form of a general carboxylate anion]]
 
This [[delocalization]] of the electron cloud means that both of the oxygen atoms are less strongly negatively charged; the positive proton is therefore less strongly attracted back to the carboxylate group once it has left; hence, the carboxylate ion is more stable and less basic as a result of resonance stabilization of the negative charge. In contrast, an [[alkoxide]] ion, once formed, would have a strong negative charge localized on theits lone oxygen atom, which would makestrongly itattract difficultany fornearby theprotons proton(indeed, toalkoxides are very strong escapebases). CarboxylicBecause acidsof thusresonance stabilization, carboxylic acids have amuch lower [[pKa]] values than alcohols. For example, the pKa value of acetic acid is 4.9 while ethanol has a pKa of 16. Hence acetic acid is a much stronger acid than ethanol. The higher the number of protons in solution, the lower the pH.<ref>{{cite book | last1= Fox|first1= Marye Anne|last2= Whitesell|first2= James K. | year = 1997 | title = Organic Chemistry | edition = 2nd|publisher=Jones and Bartlett Publishers | location = Sudbury, MA| isbn = 0-7637-0178-5 }}</ref>
 
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