Alkane or Alkene?

📌 CONCEPT: When 2-methylpropane and 2-methylpropene react together, they undergo a substitution reaction to form a single product, indicating that the more stable alkane is formed from the alkene.

📐 RULE / FORMULA: This type of reaction occurs due to the thermodynamic stability of alkanes over alkenes, where the energy released during the formation of a new C-H bond is greater than the energy required to break the C=C bond.

💡 WORKED EXAMPLE: Consider the reaction between 2-methylpropane (isobutane) and 2-methylpropene (isobutylene). The alkene undergoes a reaction with the alkane to form a new C-H bond, releasing energy and forming the more stable alkane product, 2,2-dimethylpropane.

⚠️ COMMON MISTAKE: Students may incorrectly assume that the reaction is an addition reaction, where the alkene adds across the double bond, resulting in a different product.