Question

What is the action of the following reagents on ethanoic acid? P$_2$O$_5$, heat.

Answer 1

Hint: Ethanoic acid is also known as acetic acid. This reaction is based on the chemical properties of acetic acid. Phosphorus pentoxide is considered to be a strong dehydrating agent. So, write down the reaction of ethanoic acid with phosphorus pentoxide, the end product will be obtained.

Complete step by step answer:
First, let us know about the ethanoic acid. It falls under the category of carboxylic acids, and is an organic compound. It is classified as a weak acid.
Now, if it is a carboxylic acid, then the carboxyl group will be attached to the methyl group, and on ionization, it completely dissociates.
Now, we have to discuss the effect of phosphorus pentoxide (P$_2$O$_5$) on ethanoic acid. As mentioned it is a strong dehydrating agent, it means it shows the exothermic nature of hydrolysis, and the reacting molecule will lose a water molecule, or ion.
It shows the reaction with the two molecules of ethanoic acid, and on heating; it forms acetic anhydride, or we can say ethanoic anhydride, and the water molecule is removed.
The chemical reaction is
CH$_3$COOH + CH$_3$COOH $\xrightarrow{P_2O_5}$ (CH$_3$-CO)$_2$O + H$_2$O
In the last we can conclude that phosphorus pentoxide with heat will show dehydrating effect, and will lead to the formation of acetic anhydride with a loss of water.

Note: Don’t get confused while writing the reaction, as we have used two molecules of ethanoic acid due to the effect of strong dehydrating agents on it. This reaction is commonly performed in the chemistry labs.