Which of the following best describes the stability of the cis and trans isomers of 1, 1, 3, 5 tetraethylcyclohexan ?

Options

A. The trans isomer is more stable than the cis.
B. The cis isomer is more stable than the trans.
C. Both have the same stability
D. The information given is not sufficient to deduce the stability of the isomers.

Answer

To determine the stability of the cis and trans isomers of 1,1,3,5-tetraethylcyclohexane, we can follow these steps:

### Step 1: Understand the Structure
1. **Identify the compound**: The compound is 1,1,3,5-tetraethylcyclohexane. This means there are four ethyl groups attached to a cyclohexane ring.
2. **Draw the cyclohexane ring**: Cyclohexane is a six-membered carbon ring.

### Step 2: Draw the Isomers
1. **Cis Isomer**: In the cis isomer, the ethyl groups attached to the same carbon atoms (1 and 3) are on the same side of the cyclohexane ring.
2. **Trans Isomer**: In the trans isomer, the ethyl groups on the same carbon atoms are on opposite sides of the cyclohexane ring.

### Step 3: Analyze Steric Hindrance
1. **Cis Isomer**: The bulkier ethyl groups in the cis configuration can lead to steric hindrance, as they are closer together.
2. **Trans Isomer**: The trans configuration allows the ethyl groups to be farther apart from each other, reducing steric hindrance.

### Step 4: Compare Stability
1. **Stability of Cis Isomer**: Due to steric hindrance, the cis isomer is generally less stable because the bulky ethyl groups repel each other when they are on the same side.
2. **Stability of Trans Isomer**: The trans isomer is more stable because the ethyl groups are positioned on opposite sides of the ring, minimizing steric interactions.

### Conclusion
- **Final Statement**: The trans isomer of 1,1,3,5-tetraethylcyclohexane is more stable than the cis isomer due to reduced steric hindrance.

---