What is the number of carbon atoms in the principal carbon chain of 2-ethyl-3-isopropylpentane? — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

The structure is a 5-carbon horizontal chain with an ethyl at C2 and an isopropyl at C3: $CH_3-CH(CH_2CH_3)-CH(CH(CH_3)_2)-CH_2-CH_3$. Tracing the longest continuous chain, we can start from the ethyl group (2C) through C2, C3, and then through the isopropyl group (2C) or the main chain end (2C). The max chain is $2 + 1 + 1 + 2 = 6$ carbons. Thus, the parent chain is a hexane.