Question

The ester is washed with 2M sodium carbonate. Why? Explain with chemical reactions. Hint: consider the basicity of the amine group and what is likely to have happened to it in an acidic environment, then consider how sodium carbonate behaves.

Answer 1

Esters undergo hydrolysis reactions, and in this case, the ester is washed with 2M sodium carbonate to undergo a basic hydrolysis reaction. Sodium carbonate reacts with the ester to form a carboxylate salt and an alcohol.

Step-by-step explanation:

Esters can undergo hydrolysis reactions, which involve the breaking of the ester bond and the formation of a carboxylic acid and an alcohol or a carboxylate salt and an alcohol, depending on the conditions. In this case, the ester is washed with 2M sodium carbonate to perform a basic hydrolysis reaction. Sodium carbonate is a strong base and can react with the ester to produce the carboxylate salt and an alcohol. The reaction can be represented as follows:

CH₂COOCH₂CH₃ (ester) + Na₂CO₃ (sodium carbonate) → CH₃COONa (carboxylate salt) + CH₂CH₂OH (alcohol)

Answer 2

When an ester is washed with 2M sodium carbonate, the purpose is to neutralize any remaining acidic impurities, particularly unreacted carboxylic acid or acid by-products from the esterification reaction.

The reaction involved in this neutralization is the reaction between the sodium carbonate and the acidic impurities.

By washing the ester with sodium carbonate, any remaining acidic impurities are neutralized, and the solution becomes more basic. This is important in subsequent steps of the reaction or purification processes, as many reactions are sensitive to the presence of acidic impurities. Additionally, the formation of carbon dioxide gas helps in removing any volatile acidic components from the solution.