IUPAC name of isobutyraldehyde is:

• A) Butanal
• B) 2-methylpropanal
• C) Ethyl ethanol
• D) Methyl butanal

To determine the IUPAC name of isobutyraldehyde, we need to analyze its structure and the naming conventions used in organic chemistry. Isobutyraldehyde is a type of aldehyde, which means it contains a carbonyl group (C=O) at the end of the carbon chain. The key is to identify the longest carbon chain and any substituents present.

Understanding Isobutyraldehyde

Isobutyraldehyde has the molecular formula C4H8O. Its structure can be visualized as a four-carbon chain with a carbonyl group at one end. The "iso" prefix indicates that there is a branching in the carbon chain. Specifically, isobutyraldehyde can be represented as follows:

• Carbon 1: Aldehyde group (–CHO)
• Carbon 2: Methyl group (–CH3)
• Carbon 3: Methyl group (–CH3)
• Carbon 4: Hydrogen (–H)

Identifying the Correct Name

Now, let's analyze the options provided:

• A) Butanal: This name refers to a straight-chain aldehyde with four carbons, but it does not account for the branching in isobutyraldehyde.
• B) 2-methylpropanal: This name indicates a three-carbon chain (propane) with a methyl group on the second carbon, which accurately describes isobutyraldehyde.
• C) Ethyl ethanol: This name does not correspond to isobutyraldehyde as it suggests a different structure entirely.
• D) Methyl butanal: This name implies a four-carbon chain with a methyl group, but it does not correctly describe the structure of isobutyraldehyde.

Final Analysis

Given the structure of isobutyraldehyde, the correct IUPAC name is indeed 2-methylpropanal (option B). This name reflects the presence of a three-carbon backbone (propane) with a methyl group on the second carbon, along with the aldehyde functional group at one end.

In summary, when naming organic compounds, it’s crucial to identify the longest carbon chain and any substituents accurately. In the case of isobutyraldehyde, the branching and the aldehyde functional group lead us to the name 2-methylpropanal.