Which of the following is Swart's reaction?

Question

Accepted Answer

Swart's reaction is a specific type of halogen exchange reaction where an alkyl halide (R-X) is converted into an alkyl fluoride (R-F) using a metal fluoride, typically silver fluoride (AgF). This reaction is particularly useful for synthesizing alkyl fluorides, which are important in various chemical applications.

Let's analyze why Option 3 is the correct answer and why the other options are incorrect:

1. **Option 3: $R-X + AgF \rightarrow R-F + AgX$**
   - **Explanation**: This is the classic representation of Swart's reaction. In this reaction, an alkyl halide (R-X) reacts with silver fluoride (AgF) to produce an alkyl fluoride (R-F) and silver halide (AgX). The use of silver fluoride is crucial because it facilitates the exchange of the halogen atom in the alkyl halide with a fluorine atom, resulting in the formation of the desired alkyl fluoride. This reaction is named after the chemist who developed it, and it is specifically designed for the synthesis of alkyl fluorides, making Option 3 the correct choice.

2. **Option 1: $RX + NaI \rightarrow RI + NaX$**
   - **Explanation**: This reaction is known as the Finkelstein reaction, not Swart's reaction. The Finkelstein reaction involves the exchange of one halogen atom for another, typically using sodium iodide (NaI) to convert an alkyl chloride or bromide into an alkyl iodide. This is not related to the synthesis of alkyl fluorides, which is the focus of Swart's reaction.

3. **Option 2: $CH_{2}=CH_{2} + Br_{2} \xrightarrow{CCl_{4}} CH_{2}(Br)-CH_{2}(Br)$**
   - **Explanation**: This reaction is an example of an electrophilic addition reaction where bromine (Br2) adds across the double bond of ethylene (CH2=CH2) to form 1,2-dibromoethane. This is a typical halogenation reaction and does not involve the exchange of halogens or the formation of alkyl fluorides, which are the key aspects of Swart's reaction.

4. **Option 4: $ROH + SOCl_{2} \rightarrow RCl + SO_{2} + HCl$**
   - **Explanation**: This reaction is known as the thionyl chloride reaction, where an alcohol (ROH) is converted into an alkyl chloride (RCl) using thionyl chloride (SOCl2). The reaction produces sulfur dioxide (SO2) and hydrogen chloride (HCl) as byproducts. This reaction is used for converting alcohols to chlorides, not for the synthesis of alkyl fluorides, and thus is unrelated to Swart's reaction.

In conclusion, Option 3 is the correct answer because it accurately represents Swart's reaction, which involves the conversion of an alkyl halide to an alkyl fluoride using silver fluoride. The other options describe different types of reactions that do not align with the specific characteristics of Swart's reaction.