Question

Total number of isomeric compounds (including stereoisomers) formed by monochlorination of 2-methylbutane is________.

Answer 1

Correct Answer: 6

Step-by-step Analysis:
2-Methylbutane (C$_5$H$_{12}$) is a branched alkane with the structure:
\[\text{CH}_3 - \text{CH(CH}_3\text{)} - \text{CH}_2 - \text{CH}_3\]
Monochlorination involves replacing one hydrogen atom with a chlorine atom. To determine the number of isomeric compounds, we need to identify all unique positions where chlorine can be attached.
Possible Monochlorination Sites:
Primary carbon at the terminal end (CH$_3$) connected to carbon 1.
Secondary carbon at position 2 (chiral center).
Secondary carbon at position 3.
Primary carbon at the terminal end (CH$_3$) connected to carbon 4.
Number of Isomeric Products:
item1-chloro-2-methylbutane: Chlorination at the terminal CH$_3$ group (carbon 1).
2-chloro-2-methylbutane: Chlorination at the chiral center (carbon 2) results in two stereoisomers (R and S configurations).
3-chloro-2-methylbutane: Chlorination at carbon 3.
4-chloro-2-methylbutane: Chlorination at the terminal CH$_3$ group (carbon 4).
Total Number of Isomers:
\[1 \text{ (from carbon 1)} + 2 \text{ (stereoisomers from carbon 2)} + 1 \text{ (from carbon 3)} + 1 \text{ (from carbon 4)} = 6 \text{ isomers}\]
Conclusion: The total number of isomeric compounds formed by monochlorination of 2-methylbutane, including stereoisomers, is 6.