When the end alkyl groups of ethyl ethanoate are interchanged, the compound formed is

Analysis

To solve this, we need to understand the structure and naming convention of esters. An ester is formed from an alcohol and a carboxylic acid. Its general formula is RCOOR', where R comes from the acid and R' comes from the alcohol.

Concept: Ester Nomenclature

1. Ethyl ethanoate is formed from: • Ethanoic acid (the acid part, which provides the "ethanoate" suffix): $CH_3COOH$ • Ethanol (the alcohol part, which provides the "ethyl" prefix): $C_2H_5OH$
2. The structure of ethyl ethanoate is: $CH_3COOCH_2CH_3$ • The "ethanoate" part is $CH_3COO-$ (2 carbons) • The "ethyl" part is $-CH_2CH_3$ (2 carbons)

Step-by-Step Solution

1. Identify the alkyl groups: In ethyl ethanoate, the acid part has 2 carbons ($CH_3$) and the alcohol part (the alkyl group) has 2 carbons ($C_2H_5$).
2. Interchange the groups: The question asks us to interchange the "end alkyl groups." • Currently, we have an ethyl group attached to an ethanoate group. • If we look at the total number of carbons available in the molecule ($CH_3COOCH_2CH_3$ has 4 carbons total), we need to rearrange them. • If we move one carbon from the alcohol side to the acid side, or vice versa, we change the identity of the ester. • Specifically, if we take the methyl group ($CH_3$) from the acid side and swap it with the ethyl group ($C_2H_5$) from the alcohol side, we get: • Acid part: Propanoic acid ($CH_3CH_2COO-$) • Alcohol part: Methyl ($CH_3-$)
3. Name the new compound: Combining these gives Methyl propanoate ($CH_3CH_2COOCH_3$).

Conclusion

By interchanging the alkyl groups (moving the carbon chain length between the acid and alcohol components), we transform ethyl ethanoate into methyl propanoate.

Exam Tip

When dealing with ester naming, remember: "Alkyl" comes from the alcohol (the part attached to the single oxygen), and "Alkanoate" comes from the acid (the part containing the carbonyl group $C=O$). If you are asked to interchange groups, simply shift the carbon count between these two sides while keeping the total number of carbons the same!