2-methylpentane is :

Options

A.
B.
C.
D.

Answer

To determine which of the given structures corresponds to 2-methylpentane, we will follow these steps:

### Step 1: Understand the Structure of 2-Methylpentane
2-Methylpentane is an alkane with a five-carbon chain (pentane) and a methyl group (–CH3) attached to the second carbon of the chain. The molecular formula for 2-methylpentane is C6H14.

### Step 2: Identify the Carbon Chain
The main carbon chain is pentane, which consists of 5 carbon atoms. We will denote these as follows:
- C1 - C2 - C3 - C4 - C5

### Step 3: Attach the Methyl Group
Since we need to place a methyl group on the second carbon (C2), we will represent the structure as:
- C1 - C2(CH3) - C3 - C4 - C5

### Step 4: Analyze the Given Options
We will analyze each of the provided Newman projections to see which one accurately represents 2-methylpentane.

#### Option A:
- Structure: H CH3 H (front) and H CH3 CH2 CH3 (back)
- Analysis: This structure does not have the correct number of carbon atoms when counted.

#### Option B:
- Structure: CH3 H CH3 (front) and H H CH2 CH3 (back)
- Analysis: Starting from the left, we have:
- C1 (CH3)
- C2 (H)
- C3 (CH3)
- C4 (H)
- C5 (CH2CH3)
This structure correctly shows a methyl group at the second carbon position.

#### Option C:
- Structure: CH3 H CH3 (front) and H H CH3 (back)
- Analysis: This structure also does not represent the correct carbon chain length.

#### Option D:
- Structure: H H CH2 CH3 (front) and H CH3 H (back)
- Analysis: This structure does not have the correct methyl group placement.

### Step 5: Conclusion
After analyzing all options, we find that **Option B** is the correct representation of 2-methylpentane.

### Final Answer:
**The correct answer is Option B.**

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