Question

explain the reaction of carboxylic acid with ammonia (3 marks )​

Answer 1

Answer:

Reactions of carboxylic acids with ammonia

It transfers a hydrogen ion to the lone pair on the nitrogen of the ammonia and forms an ammonium ion. If you mix together a solution of ethanoic acid and a solution of ammonia, you will get a colorless solution of ammonium ethanoate.

Answer 2

Answer:

Using the definition of an acid as a "substance which donates protons (hydrogen ions) to other things", the carboxylic acids are acidic because of the hydrogen in the -COOH group. In solution in water, a hydrogen ion is transferred from the -COOH group to a water molecule. For example, with ethanoic acid, you get an ethanoate ion formed together with a hydroxonium ion, H3O+.

This reaction is reversible and, in the case of ethanoic acid, no more than about 1% of the acid has reacted to form ions at any one time. (This is a rough-and-ready figure and varies with the concentration of the solution.)

These are therefore weak acids.

CH3COOH+H2O⇌CH3COO−+H3O+(1)(1)CH3COOH+H2O⇌CH3COO−+H3O+

This equation is often simplified by removing the water to:

CH3COOH(aq)⇌CH3COO−(aq)+H+(2)(2)CH3COOH(aq)⇌CH3COO−(aq)+H+

However, if you are going to use this second equation, you must include state symbols. They imply that the hydrogen ion is actually attached to a water molecule.