Question

Identify structure of 2,3-dibromo-1-phenylpentane.

• A.
• B.
• C.
• D.

Answer 1

The Correct Option is C

To identify the structure of 2,3-dibromo-1-phenylpentane, let's break down and understand the name as per IUPAC nomenclature rules:

1. The base name "pentane" indicates a five-carbon alkane chain.
2. A "phenyl" group at position 1 implies a benzene ring (phenyl) is attached to the first carbon of this chain.
3. There are two bromine atoms attached at positions 2 and 3 of the carbon chain, indicated by "2,3-dibromo".

Let's now analyze the given options to determine which structure represents 2,3-dibromo-1-phenylpentane:

• Option 1: The structure shows incorrect placement of the bromine atoms and the phenyl group.
• Option 2: This structure similarly misplaces the substituents according to our IUPAC breakdown.
• Option 3: Here, the structure accurately places a phenyl group at the first carbon, and the bromine atoms at the second and third carbons:

Thus, Option 3 correctly depicts 2,3-dibromo-1-phenylpentane.

• Option 4: The arrangement doesn't conform to the specifications given in the name.

Therefore, the correct answer is represented by the structural diagram in Option 3.

Answer 2

The IUPAC name 2,3-dibromo-1-phenylpentane indicates that:
- There is a phenyl group attached to the first carbon of the pentane chain.
- Bromine atoms are attached to the second and third carbons of the chain.

In the options provided, structure 3 matches this description, with a phenyl group at the first carbon and bromine atoms at the second and third carbons.

Thus, the correct structure is: Structure 3