Question

The number of possible monohalogen derivatives for the alkyl halide having molecular formula \(\mathrm{C_4H_9X}\) is

• A. 3
• B. 2
• C. 4
• D. 1

Hint:

Always consider both chain isomerism and position isomerism while counting haloalkane derivatives.

Answer 1

The Correct Option is C

Step 1: Understand the given molecular formula.
The molecular formula \(\mathrm{C_4H_9X}\) represents butyl halides, obtained by replacing one hydrogen atom of butane with a halogen atom.

Step 2: Write all possible structural isomers.
Butane has two carbon skeletons:
– n-Butane
– Isobutane

Step 3: Possible monohalogen derivatives.
From n-butane:
1. 1-Halobutane
2. 2-Halobutane
From isobutane:
3. 1-Halo-2-methylpropane (isobutyl halide)
4. 2-Halo-2-methylpropane (tert-butyl halide)

Step 4: Count the derivatives.
Total monohalogen derivatives \(= 4\).

Step 5: Conclusion.
The number of possible monohalogen derivatives is \(4\).