In the following the most stable configuration of n - butane is

Options

A.
B.
C.
D.

Answer

To determine the most stable configuration of n-butane, we need to analyze the different conformations of the molecule and identify which one minimizes steric repulsion between the bulky methyl groups. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Structure of n-Butane
n-Butane (C4H10) consists of four carbon atoms arranged in a straight chain. The molecular structure can be represented as:
- C1 - C2 - C3 - C4
Each carbon atom is bonded to hydrogen atoms to satisfy the tetravalency of carbon.

### Step 2: Identify the Different Conformations
There are several conformations of n-butane, primarily:
- Staggered conformation
- Eclipsed conformation

In the staggered conformation, the hydrogen atoms (or methyl groups) on adjacent carbons are positioned as far apart as possible, while in the eclipsed conformation, they are aligned with each other, leading to increased steric hindrance.

### Step 3: Count the Atoms in Each Configuration
For each of the given options, count the number of carbon and hydrogen atoms. In n-butane, there are 4 carbon atoms and 10 hydrogen atoms in total.

### Step 4: Analyze Steric Repulsion
The stability of the conformations is influenced by steric repulsion between the bulky groups (in this case, the methyl groups). The more distant the bulky groups are from each other, the lower the steric repulsion, leading to greater stability.

### Step 5: Identify the Most Stable Configuration
Among the various configurations:
- The configuration where the two methyl groups are positioned 180 degrees apart (anti conformation) is the most stable. This is because it minimizes steric hindrance and allows the bulky groups to be as far apart as possible.

### Conclusion
After analyzing the configurations, the second option, where the methyl groups are positioned at a dihedral angle of 180 degrees, is the most stable configuration of n-butane.

### Final Answer
The most stable configuration of n-butane is **Option 2**.

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