Question

use the following three structures to answer th question below. the relationship between i and iii is: diastereomers enantiomers constitutional isomers same compound

Explanation:

Step1: Define isomer types

Enantiomers are non - superimposable mirror images. Diastereomers are stereoisomers that are not enantiomers. Constitutional isomers have the same molecular formula but different connectivity of atoms.

Step2: Analyze structures I and III

Count the number of each type of atom in I and III. They have the same molecular formula ($C_5H_{12}O_4$). But the connectivity of the hydroxyl ($-OH$) groups and the carbon - carbon bonds is different. So they are constitutional isomers.

Answer:

C. constitutional isomers