Question

determine which structure(s) correspond to a cis isomer.

Explanation:

Step1: Recall definition of cis - isomer

Cis - isomers have identical groups on same side of ring.

Step2: Examine structure (i)

Two $NH_2$ groups are on same side, so it's cis.

Step3: Examine structure (ii)

Two $NH_2$ groups are on opposite sides, so it's trans.

Step4: Examine structure (iii)

Two $NH_2$ groups are on same side, so it's cis.

Step5: Examine structure (iv)

Two $NH_2$ groups are on opposite sides, so it's trans.

Answer:

In cis - isomers, identical groups are on the same side of the ring. Analyzing the given structures:

• In structure (i), the two $NH_2$ groups are on the same - side of the ring, so it is a cis - isomer.
• In structure (ii), the two $NH_2$ groups are on opposite sides of the ring, so it is a trans - isomer.
• In structure (iii), the two $NH_2$ groups are on the same side of the ring, so it is a cis - isomer.
• In structure (iv), the two $NH_2$ groups are on opposite sides of the ring, so it is a trans - isomer.

So the structures that correspond to cis - isomers are (i) and (iii).