The IUPAC name of
CH3−CH|CH3−C|CH3−CH|CHO−CH2−CH2−CH3 is?
3,4-Dimethy-2-propylpentanal
Although the longest chain from either end is 7-carbons long, the correct way to start numbering is from the aldehyde -CHO carbon.
This leaves us with two options.
When there are two or more longest chains, we choose to number in such a way that then are maximum number of substituents.
Option I is more appropriate as it has 3 substituents compared to option II, which has only one substituent at C2.
Word root = pent
Primary suffix = ane
Secondary suffix = al
Secondary prefix = 3,4-dimethyl-1,2-propyl
Alphabetically 3,4 - dimethyl precedes 2-propyl hence the answer is 3,4-Dimethyl-2-propylpentanal