Question

Iso-propyl bromide on Wurtz reaction gives:
A. Hexane
B. Propane
C. 2, 3-dimethylbutane
D. Neo-hexane

Answer 1

Hint: The compound formed is a saturated hydrocarbon. Saturated hydrocarbons are the type of hydrocarbon where the carbon-carbon single bond is present.

Complete Step by Step Solution:
Wurtz reaction is a type of coupling reaction where sodium metal undergoes a reaction with 2 molecules of an alkyl halide in presence of dry ether to form a higher alkane. In the given reaction dry ether is used as a solvent.

When 2 molecules of iso-propyl bromide react with sodium metal in presence of dry ether 2, 3-dimethylbutane is obtained as the main product.
The reaction of Isopropyl bromide with sodium is shown below.

Image: Reaction of Isopropyl bromide with sodium

In the general reaction, the first electron transfer takes place from the sodium metal to the halogen group which results in the formation of the alkyl radical and metal halide. After that, another electron from other sodium attacks the alkyl radical to form an alkyl anion. The nucleophilic carbon of the alkyl anion replaces the halogen of an alkyl halide by nucleophilic substitution reaction and leads to the formation of a carbon-carbon covalent bond.

In the free radical mechanism for the preparation of alkanes by Wurtz reaction, there is a possibility that alkene is also produced as a side product.
Thus iso-propyl bromide on Wurtz reaction gives 2, 3-dimethylbutane. Therefore, option C is correct.

Note: In the Wurtz reaction, only symmetric alkanes are produced as a mixture of alkanes as products are produced on the reaction of different alkanes and hence these mixtures are very difficult to separate.