|Class 12 Chemistry Aldehydes Ketones Acids||Comparison of acidic strength of Alcohol , Phenols and Carbo|
Comparison of acidic strength of alcohol , phenols and carboxylic acid
It’s seen that more the ion is stablized , more the reaction will be favoured in found direction.Below you can see carboxylic acid is resonance stabilized. So, it is more stable and on the other hand the R group attached to O- in alcohol intensifies its charge. Hence, the stability is lowered in mparison to carboxylic acid.
Phenols and carboxylic acid : Acidic character
Similarly, if we look for phenoxide ion and carboxylate ion that is formed by phenol and carboxylic acid after loosing hydrogen ion, we can easily make out that carboxylate ion is more stabilized. In it negative charge resides on electronegative ion (resonating structure ) whereas in case of phenoxide ion the negative charge is on carbon.let’s see. the structures below :
That is the reason ,carboxylic acid is stronger than phenols .
Reactions to prove acidic character of carboxylic acid
Reaction involving OH group: In this we react carboxylic acid with compounds like With PCl5 , PCl3 , SOCl2.
3.Reaction involving COOH group
The acids on reduction in presence of reducing agents like are Li AlH4 etc forms alcohols that is :