Which of the following compounds is isomeric with 2,2,4,4-tetramethylhexane?

Options

A. 3-ethyl-2,2-dimethylpentane
B. 4-isopropylheptane
C. 4-ethyl-3-methyl-4-n-propyloctane
D. 4,4-diethyl-3-methylheptane

Explanation

To determine which compound is isomeric with 2,2,4,4-tetramethylhexane, we need to follow these steps:

### Step 1: Identify the Molecular Formula of 2,2,4,4-Tetramethylhexane
2,2,4,4-Tetramethylhexane has the following structure:
- It is a hexane (6 carbon atoms) with four methyl (−CH₃) groups attached.
- The molecular formula can be derived as follows:
- Hexane contributes 6 carbon atoms (C₆).
- Four methyl groups contribute 4 additional carbon atoms (C₄).
- Therefore, the total number of carbon atoms is 10 (C₁₀).
- The number of hydrogen atoms can be calculated as follows:
- The general formula for alkanes is CₙH₂ₙ₊₂. For C₁₀, it would be H₂₁₊₂ = H₂₂.
- However, due to the presence of branching (methyl groups), the actual number of hydrogen atoms is 20 (H₂₀).

Thus, the molecular formula of 2,2,4,4-tetramethylhexane is C₁₀H₂₀.

### Step 2: Check the Options for Isomers
We need to check the given options to see which one has the same molecular formula (C₁₀H₂₀).

1. **Option 1: 3-Ethyl-2,2-dimethylpentane**
- Structure: C₁₀H₂₀
- This matches the molecular formula of 2,2,4,4-tetramethylhexane.

2. **Option 2: Isopropylheptane**
- Structure: C₁₀H₂₂
- This does not match the molecular formula of 2,2,4,4-tetramethylhexane.

### Step 3: Conclusion
Since only 3-ethyl-2,2-dimethylpentane has the same molecular formula (C₁₀H₂₀) as 2,2,4,4-tetramethylhexane, it is the isomeric compound.

### Final Answer
The compound that is isomeric with 2,2,4,4-tetramethylhexane is **3-ethyl-2,2-dimethylpentane**.