**Ionic and Free Radical Reactions in Wurtz Reaction**

The Wurtz reaction is a chemical reaction that allows the synthesis of alkyl halides using alkyl halides as starting materials. It is named after Charles-Adolphe Wurtz, who first reported this reaction in 1855. The Wurtz reaction involves the coupling of two alkyl halides in the presence of sodium metal, resulting in the formation of a higher molecular weight alkane.

**Ionic Reaction:**

In the Wurtz reaction, the reaction mechanism involves an ionic pathway. The alkyl halides, which are polar molecules, dissociate into their respective ions in the presence of a strong base like sodium. The reaction proceeds as follows:

1. The alkyl halides (R-X) dissociate into their respective ions R+ and X-.
2. Sodium metal (Na) reacts with the halide ion (X-) to form sodium halide (NaX) and releases an electron.
3. The released electron reacts with the alkyl cation (R+) to form a new alkyl radical (R°).
4. The alkyl radical (R°) then reacts with another alkyl halide (R-X) to form a higher molecular weight alkane (R-R) and regenerate the alkyl cation (R+).
5. The overall reaction can be represented as: 2R-X + 2Na → R-R + 2NaX

**Free Radical Reaction:**

In addition to the ionic pathway, the Wurtz reaction can also proceed via a free radical pathway. This mechanism occurs when the reaction is carried out in the absence of a strong base. The reaction proceeds as follows:

1. The alkyl halides (R-X) undergo homolytic cleavage, resulting in the formation of alkyl radicals (R°) and halogen radicals (X°).
2. The alkyl radicals (R°) then react with each other to form a higher molecular weight alkane (R-R).
3. The halogen radicals (X°) combine to form a diatomic halogen molecule (X-X).
4. The overall reaction can be represented as: 2R-X → R-R + X-X

**Comparison:**

- The ionic pathway involves the formation and reaction of charged species, while the free radical pathway involves the formation and reaction of uncharged species.
- The ionic pathway requires the presence of a strong base like sodium, while the free radical pathway does not.
- The ionic pathway proceeds via the formation of alkyl cations and radicals, while the free radical pathway proceeds through the formation of alkyl radicals and halogen radicals.
- The ionic pathway typically results in higher yields and fewer side reactions compared to the free radical pathway.

Overall, the Wurtz reaction can proceed via both ionic and free radical pathways, depending on the reaction conditions. The choice of pathway can have an impact on the yield and selectivity of the reaction.