Question

Circle the longest continuous carbon chain.
1) 2
2) 3
3) 4
4) 5

Answer 1

To find the longest continuous carbon chain, locate the chain with the most carbon atoms and number the carbons to give substituents the lowest numbers. If the LCC has five carbons, it's called pentane, with modifications named according to their positions, such as 2,3-dichloro-3-methylpentane.

Step-by-step explanation:

To determine the longest continuous carbon chain (LCC) in organic compounds, follow these steps:

1. Identify the longest chain of carbon atoms, which will serve as the parent chain. For example, if the longest chain has eight carbon atoms, the parent hydrocarbon is known as octane.
2. Number the carbon atoms in the parent chain from the end that gives the substituents the lowest possible numbers. This optimizes the chain numbering to ensure the correct naming of the molecule according to IUPAC nomenclature rules.

In a practical application, if one identifies a chain with five carbon atoms as the longest one, the base molecule is called pentane. For instance, if there are chlorine substituents or other groups attached to this chain, their positions are indicated using the chain numbering assigned in the earlier step. Consequently, a molecule with chlorine substituents on the second and third carbon atoms, along with a methyl group on the third carbon atom, is correctly named as 2,3-dichloro-3-methylpentane.