Question

Achiral stereoisomer(s) is(are) possible for 

• A. (A)
• B. (B)
• C. (C)
• D. (D)

Hint:

To determine achirality, check for symmetry. If a molecule has a plane of symmetry or an inversion center, it is achiral.

Answer 1

The Correct Option is C, D

To determine which of the given compounds can have achiral stereoisomers, we need to understand the concept of chirality and identify if a compound can exist in a form that does not possess chirality (i.e., a meso compound).

Let's analyze each compound:

1. Option (A): The compound is 2-butyne, a simple alkyne with symmetry along the triple bond axis. However, this molecule does not have any chiral centers, which means it is already achiral in its current form and no separate achiral stereoisomer would be derived.
2. Option (B): This compound is 2,2'-dibromo-1,1'-binaphthyl-2,2'-dicarboxylic acid. This structure is typically helical and can have axial chirality. The presence of stereogenic centers might lead to chiral isomers, making it unlikely to have an achiral stereoisomer.
3. Option (C): The given compound is tartaric acid. Tartaric acid can exist as a meso compound due to the internal plane of symmetry, making it achiral despite having stereogenic centers. Thus, one of its stereoisomers is achiral.
4. Option (D): The compound is 1,3-dimethylcyclopentane. This can achieve an achiral conformation due to the possibility of symmetric positions about the plane of the cyclopentane ring.

Conclusion: The correct options representing compounds that can have achiral stereoisomers are (C) and (D).