Question

what can be inferred about the pair of molecules shown below?
select the correct answer below:
the molecules are identical.
the molecules are enantiomers.
neither molecule contains a chiral center.
each molecule contains three chiral centers.

Explanation:

• For the claim "The molecules are identical":
• The first molecule has two chlorine atoms in the wedge configuration (coming out of the plane), while the second has them in the dash configuration (going into the plane). So, they are not identical.
• For the claim "The molecules are enantiomers":
• Enantiomers are non - superimposable mirror images. Here, each molecule has two chiral centers (carbon atoms attached to four different groups). But the relationship between these two molecules is that of meso - compounds (if we consider the whole molecule, due to internal symmetry, they are not enantiomers).
• For the claim "Neither molecule contains a chiral center":
• A chiral center is a carbon atom bonded to four different groups. In these molecules, the two carbon atoms attached to chlorine are chiral centers (they are attached to Cl, H, and two different alkyl groups). So, this option is wrong.
• For the claim "Each molecule contains three chiral centers":
• Counting the chiral centers: In each molecule, there are two carbon atoms (the ones with Cl) that are chiral centers (attached to four different groups). So, this option is wrong.

Since none of the other options are correct, we need to re - evaluate. If we consider the fact that in each molecule, there are two chiral centers (the carbons with Cl). But if we check the symmetry, we can find that these molecules are actually identical when considering rotation and the overall structure (due to the symmetry of the molecule, the orientation of Cl (wedge or dash) does not create a real difference as the molecule can be rotated to match the other).

Answer:

The molecules are identical.