Answer
(a) 2,3-dimethylhexane; $CH_{3}CH_{2}CH_{2}CH(CH_{3})CH(CH_{3})CH_{3}$
(b) 2,3-dimethyloctane; $CH_{3}CH_{2}CH_{2}CH_{2}CH_{2}CH(CH_{3})CH(CH_{3})CH_{3}$
(c) 3-ethylheptane; $CH_{3}CH_{2}CH_{2}CH_{2}CH(CH_{2}CH_{3})CH_{2}CH_{3}$
(d) 3-ethyl-2-methylhexane; $CH_{3}CH(CH_{3})CH(CH_{2}CH_{3})CH_{2}CH_{2}CH_{3}$
Structure is given in the attached document
Work Step by Step
Structures are drawn in the attached file above.
