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: Understanding the Concept:
In the Wurtz reaction, two molecules of an alkyl halide react with sodium in dry ether to form a symmetrical alkane: \(2\text{RX} + 2\text{Na} \to \text{R-R} + 2\text{NaX}\).

Step 2: Key Formula or Approach:
Write the product 2,2,5,5-tetramethylhexane and cut it in the middle (between C3 and C4) to find the alkyl group R.

Step 3: Detailed Explanation:
2,2,5,5-Tetramethylhexane: \((\text{CH}_3)_3\text{C}-\text{CH}_2-\text{CH}_2-\text{C}(\text{CH}_3)_3\).
Cutting the central \(\text{CH}_2-\text{CH}_2\) bond gives two groups \((\text{CH}_3)_3\text{C}-\text{CH}_2-\) (neopentyl).
So the halide is neopentyl chloride, \((\text{CH}_3)_3\text{C}-\text{CH}_2-\text{Cl}\), which is option B.
Option A (isobutyl chloride) would give 2,5-dimethylhexane. Option D (2-chlorobutane) would give 3,4-dimethylhexane.

Final Answer:
The Wurtz reaction of neopentyl chloride gives the product, option (B). \[ \boxed{(\text{CH}_3)_3\text{C}-\text{CH}_2-\text{Cl}} \]