There are eight diastereomers of 1,2,3,4,5,6-hexachlorocyclohexane. One of them is drawn. Draw the other seven in the cyclohexane framework below (5 points). One isomer loses HCl in an E2 reaction nearly 1000 times more slowly than the others. Circle the isomer that reacts so slowly, draw its corresponding chair conformers and explain the reason for the slow rate. (5 points).

Attached below diagram of the eight diastereomers

The Isomer that reacts so slowly is DIASTEREOMER 8

Explanation:

The Isomer that reacts so slowly is DIASTEREOMER 8 in an E2 reaction and this is because no pair of chlorine and hydrogen atoms can assume the anti-periplanar orientation that is preferred in an E2 elimination

attached below is Diagram of the eight diastereomers ( screen shot from my drawing tool )

the answer your looking for is c).