Stereochemistry

To determine the chirality of molecules X and Y, we need to analyze their structures for the presence of a chiral center (a carbon atom with four different groups attached).

Molecule X:

• The structure shows a carbon atom bonded to H, CH₃, Br, and another carbon (which is part of the chain).
• Since the central carbon has four different substituents (H, CH₃, Br, and the rest of the molecule), it is a chiral center.
• Therefore, molecule X is chiral.

Molecule Y:

• The structure shows a carbon atom bonded to H, Br, and two other identical carbon atoms (the rest of the chain on both sides).
• Since the central carbon has two identical substituents (the two carbons), it is not a chiral center.
• Therefore, molecule Y is achiral.

Conclusion:

• X = chiral, Y = achiral.

The correct answer is C: X = chiral, Y = achiral.