Which is a correct name according to IUPAC system ?

Options

A. 2,3-Diemthylhexane
B. 3-Ethyl-2-methylpentane
C. 3,3-Dimethylpentane
D. 2-Ethyl-2-methylpentane

Explanation

To determine the correct name according to the IUPAC system from the given options, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Analyze Option A: 2,3-dimethylhexane**
- **Structure Drawing**: Hexane has 6 carbon atoms. The structure will have methyl groups at the 2nd and 3rd positions.
- **Numbering**: Number the carbon chain from one end to the other. Starting from one end, we have:
- 1 - 2 (methyl) - 3 (methyl) - 4 - 5 - 6
- **Spelling Check**: The name is correct in terms of structure, but there is a spelling mistake in the name. The correct spelling should be "2,3-dimethylhexane."
- **Conclusion**: This option is incorrect due to the spelling error.

2. **Analyze Option B: 3-ethyl-2-methylpentane**
- **Structure Drawing**: Pentane has 5 carbon atoms. The structure will have an ethyl group at the 3rd position and a methyl group at the 2nd position.
- **Numbering**: Number the carbon chain:
- 1 - 2 (methyl) - 3 (ethyl) - 4 - 5
- **Re-check Numbering**: If we start numbering from the other end, we still get:
- 1 - 2 - 3 - 4 - 5
- **Conclusion**: The structure and naming are correct according to IUPAC rules. This option is correct.

3. **Analyze Option C: 3,3-dimethylpentane**
- **Structure Drawing**: Pentane has 5 carbon atoms. The structure will have two methyl groups at the 3rd position.
- **Numbering**: Number the carbon chain:
- 1 - 2 - 3 (methyl) - 4 - 5 (methyl)
- **Re-check Numbering**: Starting from the other end gives:
- 1 - 2 - 3 - 4 - 5
- **Conclusion**: The structure and naming are correct according to IUPAC rules. This option is also correct.

4. **Analyze Option D: 2-ethyl-2-methylpentane**
- **Structure Drawing**: Pentane has 5 carbon atoms. The structure will have an ethyl group and a methyl group both at the 2nd position.
- **Numbering**: Number the carbon chain:
- 1 - 2 (ethyl, methyl) - 3 - 4 - 5
- **Re-check Numbering**: If we start from the other end, we would have:
- 1 - 2 (methyl, ethyl) - 3 - 4 - 5 - 6 (this creates a longer chain).
- **Conclusion**: The naming is incorrect as the longest chain should be prioritized. This option is incorrect.

### Final Conclusion:
- **Correct Options**: B (3-ethyl-2-methylpentane) and C (3,3-dimethylpentane) are correct according to IUPAC nomenclature.
- **Incorrect Options**: A (2,3-dimethylhexane) and D (2-ethyl-2-methylpentane) are incorrect.