See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Alkene Stability Analysis **Key Principle:** Alkene stability increases with the number of alkyl groups attached to the double bond carbons (more substituted = more stable). **Analyzing each structure:** **(1) $H_2C=CH_2$ (Ethene)** - Tetrasubstituted: 4 hydrogens, 0 alkyl groups - Least stable **(2) $CH_3CH=CH_2$ (Propene)** - Trisubstituted: 3 hydrogens, 1 alkyl group ($CH_3$) - One carbon of the double bond has one alkyl substituent **(3) $(C_2H_5)CH=CH_2$ (1-Butene)** - Trisubstituted: 3 hydrogens, 1 alkyl group ($C_2H_5$) - Similar substitution pattern to option (2) **(4) $(CH_3)_2CH-CH=CH_2$ (2-Methylpropene)** - **Disubstituted:** 2 hydrogens, 2 alkyl groups - The double bond carbon bears two methyl groups → **highest substitution** **Ranking by stability:** $$\text{(1)} < \text{(2), (3)} < \text{(4)}$$ **Option (2) is most stable** because it represents **2-methylpropene (isobutylene)** with a disubstituted double bond bearing two bulky alkyl groups, providing maximum hyperconjugation and steric stabilization.