Notes On Carboxylic Acids: Properties - I - CBSE Class 12 Chemistry
The first four members of carboxylic acids are fairly soluble in water due to the ability of the carboxyl group to form hydrogen bonds with water molecules. Higher carboxylic acids are virtually insoluble in water due to the greater influence of the hydrocarbon part. The boiling points of carboxylic acids are higher than that of aldehydes, ketones and alcohols of comparable molecular weights. Unlike phenols, carboxylic acids react even with weaker bases such as carbonates and bicarbonates to form the corresponding salts with the evolution of carbon dioxide. The reaction of carboxylic acids with carbonates and bicarbonates is used to detect the presence of the carboxyl group in an organic compound. The strength of the electron-withdrawing substituent determines the magnitude of the effect on acidity. Ex: The acidity of carboxylic acids increases with an increase in the number of electron-withdrawing groups. Ex: Trichloro acetic acid is more acidic than dichloro acetic acid and monochloro acetic acid. Electron-donating groups decrease the acidity by destabilising the anion by intensifying the negative charge.

#### Summary

The first four members of carboxylic acids are fairly soluble in water due to the ability of the carboxyl group to form hydrogen bonds with water molecules. Higher carboxylic acids are virtually insoluble in water due to the greater influence of the hydrocarbon part. The boiling points of carboxylic acids are higher than that of aldehydes, ketones and alcohols of comparable molecular weights. Unlike phenols, carboxylic acids react even with weaker bases such as carbonates and bicarbonates to form the corresponding salts with the evolution of carbon dioxide. The reaction of carboxylic acids with carbonates and bicarbonates is used to detect the presence of the carboxyl group in an organic compound. The strength of the electron-withdrawing substituent determines the magnitude of the effect on acidity. Ex: The acidity of carboxylic acids increases with an increase in the number of electron-withdrawing groups. Ex: Trichloro acetic acid is more acidic than dichloro acetic acid and monochloro acetic acid. Electron-donating groups decrease the acidity by destabilising the anion by intensifying the negative charge.

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