Question

The structure of isobutyl group in an organic compound is
A. (1) `CH_(3)-underset(|)(CH)-CH_(2)-CH_(3)`
B. (2) `CH_(3)-CH_(2)-CH_(2)-CH_(2)-`
C. (3) `CH_(3)-underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C )-`
D. (4)

Answer 1

The prefix iso always describes the following structural unit:
`CH_(3)-underset(CH_(3))underset(|)(CH)-`
which is present only in fourth alkyl group:
`CH_(3)-underset(Isobutyl)underset(CH_(3))underset(|)(CH)-CH_(2)-`