Question

Which acid of the pair shown here would you expect to be stronger?
$Ph - COOH{\text{ }}or{\text{ }}C{H_3}COOH$

Answer 1

Hint: In case of phenol the ion formed is more stable due to the delocalization of charge. Also, the more stable the ion formed after removal of hydrogen is more acidic.

Complete step by step answer:
First we need to look at the structure of phenol, when it loses the hydrogen atom a phenoxide ion is formed and the charge is delocalized all over the molecule and hence the structure is much more stable.
Now coming to the structure of \[Ph - COOH\], in this when this acid loses a hydrogen then we get the ion which is \[Ph - CO{O^ - }\] , the negative charge on the compound then delocalized to the other oxygen and the double bond between the oxygen and carbon moves to other oxygen. Such delocalization of ions leads to a stable structure.
When we consider the structure of \[C{H_3}COOH\], when this compound loses an Hydrogen it forms the ion \[C{H_3}CO{O^ - }\], clearly no delocalization of charge happens in such structure. And due to no delocalization present in this ion, this ion is less stable as compared to the \[Ph - CO{O^ - }\].
More stable the ion formed after removal of hydrogen is more acidic the acid is, since, \[Ph - CO{O^ - }\]is more stable as compared to \[C{H_3}CO{O^ - }\]; we can say that the acid \[Ph - COOH\]is stronger as compared with \[C{H_3}COOH\].

Note:
We must know that the both the acids given in this question are organic acids and organic acids are weak as compared to the minerals acids. Organic acids are used in many places such as in oil and gas treatments. Organic acids are less reactive with metals and are used at high temperature when long contact with acid is required. Also the organisms produce many organic acids such as lactic acid, amino acids, etc. which are required for our life.