See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

# Analysis of Conformational Stability **Identify the structures:** All four options show different conformations of 2,2-dimethylpropane (neopentane), $C(CH_3)_4$, viewed along a C-C bond. **Key stability criterion:** Staggered conformations are more stable than eclipsed conformations because they minimize steric repulsion between bonds on adjacent carbons. **Analyze each option:** - **(A)** All four $CH_3$ groups are arranged in a **staggered orientation** around the central carbon. Maximum separation between methyl groups → **minimum steric strain**. - **(B)** Two $CH_3$ groups are **eclipsed** with H atoms on the back carbon → increased steric repulsion. - **(C)** Two $CH_3$ groups are **directly eclipsed** with each other → severe steric clash (unfavorable). - **(D)** One $CH_3$ is eclipsed with another $CH_3$ → steric congestion. **Conclusion:** Option **(A)** shows the most staggered arrangement with all methyl groups maximally separated, resulting in the **lowest energy and greatest stability**.