Question

Which of the following can show optical isomerism? (a) 2 -bromo- 2 -chlorobutane (b) 2 -methylpropane (c) 2,2 -dimethyl-1-butanol (d) 2,2,4 -trimethylpentane

Short answer

a) 2-bromo-2-chlorobutane b) 2-methylpropane c) 2,2-dimethyl-1-butanol d) 2,2,4-trimethylpentane Answer: a) 2-bromo-2-chlorobutane

Step-by-step solution

Analyze the structure of 2-bromo-2-chlorobutane

Draw the structure of 2-bromo-2-chlorobutane. Identify the second carbon atom which is connected to a bromine, a chlorine, a hydrogen, and the rest of the carbon chain. Notice that it has four different groups attached, making it a chiral center.

Analyze the structure of 2-methylpropane

Draw the structure of 2-methylpropane. There is a carbon atom connected to three methyl groups and a hydrogen atom. In this case, the carbon atom is not connected to four different groups, so it does not have a chiral center.

Analyze the structure of 2,2-dimethyl-1-butanol

Draw the structure of 2,2-dimethyl-1-butanol. In this molecule, there isn't any carbon atom connected to four different groups. No chiral center is present.

Analyze the structure of 2,2,4-trimethylpentane

Draw the structure of 2,2,4-trimethylpentane. Again, there is no carbon atom connected to four different groups, so it does not have a chiral center.

Identify the compound that can show optical isomerism

We have analyzed the structures of all four compounds and found that only 2-bromo-2-chlorobutane has a chiral center. Therefore, it is the compound that can show optical isomerism, and the answer is (a) 2-bromo-2-chlorobutane.