Question

which of the following statements is true about the molecules shown below?
select the correct answer below:
both are chiral.
both are achiral.
the first molecule (a) is chiral, and the second molecule (b) is achiral.
they are stereoisomers.

Explanation:

Step1: Determine chirality of molecule (a)

A chiral carbon has four different groups attached. In molecule (a), the central carbon is attached to \(CH_3\), \(H\), \(Cl\), and \(Br\) (four different groups). So, molecule (a) is chiral.

Step2: Determine chirality of molecule (b)

In molecule (b), the central carbon is attached to \(CH_3\), \(H\), \(H\), and \(Br\) (only three different groups as there are two \(H\) atoms). So, molecule (b) is achiral.

Step3: Check stereoisomerism

Stereoisomers have the same connectivity but different spatial arrangement. Since molecule (b) is achiral (due to two same groups) and molecule (a) is chiral, they cannot be stereoisomers (as stereoisomerism requires a chiral center - related 3D arrangement consideration which is not valid here as one is achiral).

Answer:

The first molecule (a) is chiral, and the second molecule (b) is achiral.