Question

Number of stereoisomers of 3-bromo-2-butanol:

• A. $2$
• B. $4$
• C. $6$
• D. $8$

Hint:

Use the formula $2^n$ for maximum number of stereoisomers, where $n$ is the number of chiral centers. Check for meso forms if symmetry is possible.

Answer 1

The Correct Option is B

- The structure of 3-bromo-2-butanol is: $$ \text{CH}_3\text{-CH(OH)-CH(Br)-CH}_3 $$ - In this molecule: - The carbon at position 2 (attached to OH) is a chiral center. - The carbon at position 3 (attached to Br) is also a chiral center. - Since there are two chiral centers, the maximum number of stereoisomers is: $$ 2^n = 2^2 = 4 $$ where \( n = \text{number of chiral centers} \). - These 4 stereoisomers include:
- A pair of enantiomers (non-superimposable mirror images).
- Another pair of enantiomers.
- No meso compound exists in this case, as there is no internal plane of symmetry due to the different substituents (OH and Br).