Answer :
Answer:
a) The IUPAC name for the structure is 3,3 - dimethyl pentane.
b) The structure for 3-ethyl-5-methyl-4-propyl heptane is drawn in the 2nd attached image to this question.
Explanation:
The first attached image contains the question (structure to be named and the (b) part of the question) and the second attached image contains the image of the (b) part of the question.
a) In naming the structure in the first attached image, the IUPAC rules were strictly followed.
The specific IUPAC rule that this question focuses on is the rule to 'always pick the longest continuous chain of carbon as the root/main structure while naming hydrocarbons'.
In this structure, the second carbon from the left as it appears in the diagram has a methyl substituent (-CH₃) and an ethyl substituent (-CH₂CH₃) attached to it. Naming the compound by counting the main compound's carbon from the first carbon from the left would have yielded a 4-carbon Sloane with those two branches; but, this would have been wrong. Because if the counting is done from the ethyl group, we obtain a longer 5-carbon main branch, thereby leading to a pentane main branch with the two methyl substituents both on the 3rd Carbon. Since they're two, IUPAC tells us that's a dimethyl.
Hence, 3,3 - dimethyl pentane.
b) This one is straight forward; 3-ethyl-5-methyl-4-propyl heptane means a main branch of 7-carbon Beltane with an ethyl substituent (-CH₂CH₃) on the 3rd Carbon, a methyl substituent (-CH₃) on the 5th Carbon and a propyl substituent (-CH₂CH₂CH₃) on the 4th Carbon.
