Total number of isomeric compounds (including stereoisomers) formed by monochlorination of 2 -methylbutane is _______.JEE Main 2024 (01 Feb Shift 2)

The monochlorination of 2-methylbutane can result in the formation of different isomeric compounds. Here's how you can calculate them:

1. Identify the different types of hydrogen atoms in the molecule. In 2-methylbutane, there are three types of hydrogen atoms:

   • 9 hydrogen atoms are in the methyl groups attached to the secondary carbon atom (Type 1).
   • 2 hydrogen atoms are in the methylene group attached to the tertiary carbon atom (Type 2).
   • 3 hydrogen atoms are in the methyl group attached to the primary carbon atom (Type 3).

2. Each type of hydrogen atom can be replaced by a chlorine atom to form a new compound.

3. Replacing a Type 1 hydrogen atom gives us 2-chloro-2-methylbutane. There's only one way to do this, so we get 1 isomer.

4. Replacing a Type 2 hydrogen atom gives us 2-chloro-3-methylbutane. There's only one way to do this, so we get 1 isomer.

5. Replacing a Type 3 hydrogen atom gives us 1-chloro-2-methylbutane. There's only one way to do this, so we get 1 isomer.

6. Now, we need to consider stereoisomers. Only 2-chloro-3-methylbutane can have stereoisomers because it has a chiral center. It can exist in two forms: R and S. So, we get 2 stereoisomers.

7. Add up all the isomers: 1 (from Type 1) + 1 (from Type 2) + 1 (from Type 3) + 2 (stereoisomers) = 5 isomers.

So, the total number of isomeric compounds (including stereoisomers) formed by monochlorination of 2-methylbutane is 5.