Freon-12 is manufactured from tetrachloromethane by

Swarts reaction

The correct answer is option 3. Swarts reaction.

Freon-12, chemically known as dichlorodifluoromethane (\(\text{CCl}_2\text{F}_2\)), is a type of chlorofluorocarbon (CFC) used extensively as a refrigerant and propellant. It is manufactured from tetrachloromethane (\(\text{CCl}_4\)) using the Swarts reaction.

The Swarts Reaction

The Swarts reaction is a method used for the fluorination of organic compounds, specifically for replacing chlorine atoms with fluorine atoms in chlorinated hydrocarbons. This reaction is named after the chemist who developed it, Adolf Swarts.

Reaction Overview:

The reaction involves treating a chlorinated hydrocarbon with fluorine gas (\(\text{F}_2\)) to produce a fluorinated derivative. In the case of tetrachloromethane, the goal is to replace two chlorine atoms with fluorine atoms to produce Freon-12. The general Swarts reaction for the production of Freon-12 can be represented as follows:

\(\text{CCl}_4 + 2 \text{F}_2 \rightarrow \text{CCl}_2\text{F}_2 + 2 \text{ClF}\)

Here is a step-by-step breakdown of the reaction:

Starting Material: Tetrachloromethane (\(\text{CCl}_4\)) is the precursor. It contains four chlorine atoms attached to a single carbon atom.

Fluorination: The reaction is carried out with fluorine gas (\(\text{F}_2\)), which is a strong fluorinating agent. Fluorine atoms replace the chlorine atoms in the tetrachloromethane molecule.

Product Formation: The final product is dichlorodifluoromethane (\(\text{CCl}_2\text{F}_2\)), where two chlorine atoms have been replaced by fluorine atoms. Along with Freon-12, chlorine fluoride (\(\text{ClF}\)) is also produced as a by-product.

Reaction Conditions: The reaction is typically conducted under controlled conditions due to the reactivity of fluorine gas. It requires careful handling and equipment resistant to fluorine’s corrosive nature.Why the Other Reactions Are Not Suitable:

Wurtz Reaction: The Wurtz reaction is used to couple two alkyl halides in the presence of sodium to form a new alkane. This method is not applicable for the production of Freon-12, as it involves different reactants and products.

Finkelstein Reaction: This reaction involves the substitution of a halogen in an alkyl halide with iodide ions. It is typically used to prepare iodinated compounds, not fluorinated ones like Freon-12.

\(\beta\)-Elimination Reaction: This reaction involves the removal of a small molecule (e.g., water or hydrogen halide) to form a double bond. It is not suitable for fluorination of chlorinated hydrocarbons.

In summary, the Swarts reaction is the appropriate method for manufacturing Freon-12 from tetrachloromethane by replacing chlorine atoms with fluorine atoms.