Question

Question #e0f1b

Answer 1

Double bonds always take priority over halogens in numbering.

Explanation:

Thus,

`"CH"_3stackrelcolor(blue)(2)("C")"H=CH-"stackrelcolor(blue)(4)("C")"H=CHCH"_2stackrelcolor(blue)(7)("C")"H"_2"Br"`

is 7-bromohepta-2,4-diene because you number from the end closest to a double bond.

Also,

`"CH"_3"CH"_2"CH="stackrelcolor(blue)(4)("C")"H-CH="stackrelcolor(blue)(2)("C")"H-"stackrelcolor(blue)(1)("C")"H"_2"Br"`

is 1-bromohepta-2,4-diene because you number from the end closest to a double bond.