Question

The refluxing of \[{\left( {C{H_3}} \right)_2}NCOC{H_3}\ ] with acid gives
A. \[{\left( {C{H_3}} \right)_2}NH + C{H_3}COOH\]
B. \[{\left( {C{H_3}} \right)_2}NCOOH + C{H_4}\]
C. \[2C{H_3}OH + C{H_3}CON{H_2}\]
D. \[2C{H_3}N{H_2} + C{H_3}COO{H_2}\]

Answer 1

Hint: \[{\left( {C{H_3}} \right)_2}NCOC{H_3}\] is an amide which is a strong alkaline compound. Amides consisting of less than five or five carbon atoms are water-soluble. On reflux with dilute acid (ex. dil.\[HCl\]), amides get hydrolysed as acid acts as a catalyst for the reaction. Acids are protic, they give their proton\[\left( {{H^ + }} \right)\] to electron-deficient atoms; bases accept the protons.

Complete Step by Step Solution:
In this reactant nitrogen of the amide functional group have lone pair to donate and carbon is electron deficient as it is directly attached to two electronegative atoms i.e., nitrogen and oxygen.

On refluxing with acid, the bond between nitrogen and carbon of amide linkage breaks because of the polarity difference between the carbon and nitrogen bond. Amide is basic, so it attacks the protons of acid and forms an amine functional group. The hydroxyl group from the water of dilute acid attaches to the carbonyl functional group as carbon is electron deficient and forms the carboxylic acid functional group. Refluxing the amide with acid results in amine and a weak acid.

It is in actuality alkaline hydrolysis of amides because reactions with hydroxyl ions are also involved but the results are the same as hydrolysis, so it is generally a hydrolysis reaction.
This is the reaction that takes place:

 Image: Acid reflux of amide

So, the option A is correct.

Additional Information: Refluxing is used in an experimental lab to heat the reaction mixture at a constant temperature without the loss of solvent. In a reflux system, solvent boils and condenses back to the reaction mixture and prevents its loss. This helps in long-time reactions to proceed in a safe and controlled way.

Note: Amides are derivative of carboxylic acids produced on reaction with solid ammonium carbonate. In turn, amide is refluxed with acid for approx 2.5 hours to form carboxylic acid.