Question

How many asymmetric carbons are present in the following molecule? HOCH$_2$CH(Br)CH(Br)CH$_2$OH

• A. 3
• B. 1
• C. 4
• D. 2

Hint:

To identify asymmetric carbons, carefully examine each carbon atom in the molecule and check if it is bonded to four distinct groups. Pay close attention to the connectivity and identity of each substituent.

Answer 1

The Correct Option is D

Step 1: Define an asymmetric carbon.
An asymmetric carbon atom (chiral center) is a carbon atom bonded to four different groups.
Step 2: Examine the structure of the given molecule: HOCH$_2$-CH(Br)-CH(Br)-CH$_2$OH.
Let's analyze each carbon atom in the chain: \begin{itemize} \item Carbon 1 (HOCH$_2$-): Bonded to -OH, -H, -H, and -CH(Br)CH(Br)CH$_2$OH. It has two identical hydrogen atoms, so it is not asymmetric. \item Carbon 2 (-CH(Br)-): Bonded to -H, -Br, -CH$_2$OH, and -CH(Br)CH$_2$OH. The four groups are different. Therefore, Carbon 2 is asymmetric. \item Carbon 3 (-CH(Br)-): Bonded to -H, -Br, -CH(Br)CH$_2$OH, and -CH$_2$OH. The four groups are different. Therefore, Carbon 3 is asymmetric. \item Carbon 4 (-CH$_2$OH): Bonded to -OH, -H, -H, and -CH(Br)CH(Br)CH$_2$OH. It has two identical hydrogen atoms, so it is not asymmetric. \end{itemize}
Step 3: Count the number of asymmetric carbons.
There are two asymmetric carbon atoms (Carbon 2 and Carbon 3) in the given molecule. Final Answer: The final answer is $\boxed{2}$