Illustrated Glossary of Organic Chemistry

Major product: The product that is produced in the greatest amount in a chemical reaction.

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	2-Bromo-2-methylpropane 99% of product Major product		1-Bromo-2-methylpropane 1% of product Minor product

When HBr is added to isobutylene, the product mixture consists mostly of 2-bromo-2-methylpropane (the major product), plus a small amount of 2-bromo-2-methylpropane (a minor product). This reaction obeys Markovnikov's rule.