Question

Which of the following compound has chiral carbon atom?

• A. 2-chlorobutane
• B. 2, 2-dichlorobutane
• C. 1-chlorobutane
• D. 2-chloro 2-methylpropane

Hint:

To identify a chiral carbon quickly, check whether the carbon atom is bonded to four different groups. If yes, the compound can show optical isomerism.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
A carbon atom is chiral (or asymmetric) if it is bonded to four different groups or atoms.
Step 2: Formula Application:
Let's check 2-chlorobutane ($CH_3-CHCl-CH_2-CH_3$): The 2nd carbon is attached to: 1. $-H$ (Hydrogen) 2. $-Cl$ (Chlorine) 3. $-CH_3$ (Methyl group) 4. $-CH_2CH_3$ (Ethyl group)
Step 3: Explanation:
Since all four groups are different, the 2nd carbon is chiral. In the other options, the 2nd carbon has either two identical Cl atoms (b), two identical H atoms (c), or three identical Methyl groups (d).
Step 4: Final Answer:
2-chlorobutane has a chiral carbon atom.