Draw Two Constitutional Isomers Of Molecular Formula C4H8O2 That Contain An Ester.
The correct answer and explanation is :
Answer:
The two constitutional isomers of molecular formula C₄H₈O₂ that contain an ester functional group are:
- Methyl propanoate (Methyl propionate) – CH₃CH₂COOCH₃
- Ethyl ethanoate (Ethyl acetate) – CH₃COOCH₂CH₃
Explanation:
1. Understanding Constitutional Isomers
Constitutional isomers (also known as structural isomers) have the same molecular formula but differ in the connectivity of atoms. Since the question specifies that the isomers must contain an ester functional group (-COO-), we focus on different ways to arrange the C, H, and O atoms while keeping the ester functionality.
2. Molecular Formula Analysis
The given molecular formula is C₄H₈O₂.
- This suggests that the molecule follows the general formula of esters, CnH₂nO₂ (which matches with C₄H₈O₂).
- The presence of oxygen atoms suggests that the compound contains either a carboxyl (-COOH), ester (-COO-), or other oxygen-containing functional groups.
- However, since the problem specifically requires esters, we exclude carboxylic acids.
3. Drawing the Two Isomers
- Methyl Propanoate (Methyl Propionate) – CH₃CH₂COOCH₃
- This ester is formed from propanoic acid (CH₃CH₂COOH) and methanol (CH₃OH).
- The ester group (-COO-) is placed between a propyl (CH₃CH₂CO-) and a methyl (CH₃) group.
- Ethyl Ethanoate (Ethyl Acetate) – CH₃COOCH₂CH₃
- This ester is formed from acetic acid (CH₃COOH) and ethanol (CH₃CH₂OH).
- The ester group (-COO-) is placed between an acetyl (CH₃CO-) and an ethyl (CH₂CH₃) group.
4. Differences Between the Isomers
- Different connectivity: Methyl propanoate has a propanoate (CH₃CH₂COO-) backbone, while ethyl acetate has an acetate (CH₃COO-) backbone.
- Different chemical properties: Slightly different boiling points and solubility due to the molecular structure.
- Different IUPAC names: Methyl propanoate vs. Ethyl acetate.
Thus, the two valid constitutional isomers of C₄H₈O₂ containing an ester group are methyl propanoate and ethyl acetate.