Question

What type or types of stereoisomers are possible for 3,4-heptadiene?

Answer 1

in 3,4-heptadiene there is no stereo center present.
for 3-heptene the stereoisomers are given in pic

Explanation:

Answer 2

Hepta-3,4-diene exists as a pair of enantiomers.

Explanation:

The condensed structural formula of hepta-3,4-diene is

`"CH"_3"CH"_2"CH=C=CHCH"_2"CH"_3`

At first glance, it appears that the compound has no stereoisomers.

But it is a derivative of allene (propadiene).

The planes of the `"CH"_2` groups in allene are perpendicular to each other, so a suitable substitution will create a chiral molecule (without a chiral carbon!).

You can check for yourself that the two structures below are indeed nonsuperimposable mirror images of each other (enantiomers).