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

  • If we compare Alcohol and carboxylic acid, we see that :


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 with metal


Reaction involving OH group: In this we react carboxylic acid with compounds like With PCl5 , PCl3 , SOCl2.


  • Reaction with alcohol : Esterification


  • Reaction with NH3


  • Formation of acid anhydride



3.Reaction involving COOH group


  • Reaction of carboxylic salt of Calcium

            Class_12_Chemistry_Carboxylic_Acid_Reaction_With_Calcium 4.Reduction reaction

  • Partial Reduction

The acids on reduction in presence of reducing agents like are  Li AlH4 etc forms alcohols that is :


  • Complete reduction : When complete reduction is carried out, it forms alkane in presence of red Phosphorous that is :


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