Final answer:
To choose the correct chain in a molecule with two possible parent chains of equal length, determine the parent chain with the highest number of branches.
Step-by-step explanation:
Chemistry: How to Choose the Correct Chain for a Molecule with Two Possible Parent Chains of Equal Length
If there are two or more longest chains of equal length, choose the parent chain with the highest number of branches on it.
Find the longest continuous chain of carbon atoms in the molecule. This is called the parent chain.
Number the carbon atoms in the parent chain, starting from the end that will give the smallest numbers to the carbon atoms where the branches originate.