Question

Which of the following alkyl chlorides on Wurtz reaction gives 2, 2, 5, 5- tetramethylhexane ?

• A. \((\text{CH}_3)_2\text{CH}-\text{CH}_2-\text{Cl}\)
• B. \((\text{CH}_3)_3\text{C}-\text{CH}_2-\text{Cl}\)
• C. \((\text{CH}_3)_2\text{CH}-\underset{\underset{\text{CH}_3}{|}}{\text{CH}}-\text{Cl}\)
• D. \(\text{CH}_3-\text{CH}_2-\underset{\underset{\text{Cl}}{|}}{\text{CH}}-\text{CH}_3\)

Hint:

Wurtz reaction joins two alkyl groups, so split the product into two equal halves.

Answer 1

The Correct Option is B

Step 1: Work backwards:
The product has a symmetrical skeleton with two $(\text{CH}_3)_3\text{C}-\text{CH}_2-$ halves joined by one new C-C bond.

Step 2: Identify the halide:
Each half must come from $(\text{CH}_3)_3\text{C}-\text{CH}_2-\text{Cl}$ with the Cl replaced by the new bond.
The isobutyl chloride in A would join two isobutyl groups, and C and D carry the chlorine on a secondary carbon, so they would join through that carbon and give a different carbon skeleton.

Final Answer:
The alkyl chloride is $(\text{CH}_3)_3\text{C}-\text{CH}_2-\text{Cl}$, option (B). \[ \boxed{(\text{CH}_3)_3\text{C}-\text{CH}_2-\text{Cl}} \]