Question

Both Freon-11 and Freon-12 are made by the reaction of carbon tetrachloride \(\left(\mathrm{CCl}_{4}\right)\) with hydrogen fluoride. Write equations for these reactions.

Short answer

Freon-11: \( \text{CCl}_4 + \text{HF} \rightarrow \text{CCl}_3\text{F} + \text{HCl} \); Freon-12: \( \text{CCl}_4 + 2\text{HF} \rightarrow \text{CCl}_2\text{F}_2 + 2\text{HCl} \).

Step-by-step solution

Understanding the Reaction

Freon-11 and Freon-12 are refrigerants made by the reaction of carbon tetrachloride (CCl₄) with hydrogen fluoride (HF). We need to write separate chemical equations for each compound formation.

Writing the Equation for Freon-11

Freon-11 is also known as trichlorofluoromethane (CCl₃F). The reaction involves the substitution of one chlorine (Cl) atom in CCl₄ with one fluorine (F) atom from HF.The reaction can be written as: \[\text{CCl}_4 + \text{HF} \rightarrow \text{CCl}_3\text{F} + \text{HCl} \]

Writing the Equation for Freon-12

Freon-12 is known as dichlorodifluoromethane (CCl₂F₂). Here, two chlorine atoms in CCl₄ are replaced by two fluorine atoms from HF.The balanced reaction is:\[\text{CCl}_4 + 2\text{HF} \rightarrow \text{CCl}_2\text{F}_2 + 2\text{HCl}\]

Balancing the Reactions

Ensure that the number of each type of atom on the reactant side equals the number on the product side. Both equations are balanced as written.

Final Review

The reactions are correctly balanced and represent the formation of Freon-11 and Freon-12 from carbon tetrachloride and hydrogen fluoride. Double-check each step to ensure accuracy.

Key concepts

Substitution Reaction

A substitution reaction is a type of chemical reaction where one atom or group of atoms in a molecule is replaced by another atom or group of atoms. This process is essential in many chemical transformations, especially in organic chemistry. In the context of forming Freon-11 and Freon-12, substitution reactions occur when chlorine atoms in carbon tetrachloride (CCl₄) are replaced with fluorine atoms from hydrogen fluoride (HF). This type of reaction is highly significant in creating new compounds with different properties from the original substance. Substitution reactions often require specific conditions or catalysts to proceed and may involve different mechanisms depending on the reactants involved.

Refrigerants

Refrigerants are chemical compounds used in cooling systems, like air conditioners and refrigerators, to absorb and release heat efficiently. They work by cycling through phases of vaporization and condensation. As they change states from liquid to gas and back, they absorb heat from the surroundings and release it elsewhere, enabling cooling. Refrigerants have several key properties:

• Low boiling point: Allows evaporation and heat absorption at low temperatures.
• Non-toxic and stable: Essential for safe long-term use in home and industrial applications.
• Non-flammable: Prevents risk of combustion during operation.
• Efficient heat exchange: Maximizes energy efficiency.

Leveraging these properties, refrigerants are central to maintaining needed temperatures in various applications. However, some common refrigerants have been linked to environmental concerns such as ozone depletion and global warming.

Freon-11

Freon-11, chemically known as trichlorofluoromethane (CCl₃F), belongs to a class of chemicals known as chlorofluorocarbons (CFCs). It was widely used in the past as a refrigerant due to its excellent thermal properties. Its formation involves the substitution of one chlorine atom in carbon tetrachloride with a fluorine atom, the reaction being:\[ \text{CCl}_4 + \text{HF} \rightarrow \text{CCl}_3\text{F} + \text{HCl} \]Freon-11 was not only a refrigerant but also served as a foam-blowing agent for products like insulation and cushions. Despite its effectiveness, Freon-11 contributes to ozone layer depletion, which has led to its phase-out under the Montreal Protocol. Modern alternatives aim to reduce environmental impacts while maintaining efficiency.

Freon-12

Freon-12, or dichlorodifluoromethane (CCl₂F₂), is another chlorofluorocarbon that was historically popular in refrigeration and air conditioning. The chemical equation for its production is:\[ \text{CCl}_4 + 2\text{HF} \rightarrow \text{CCl}_2\text{F}_2 + 2\text{HCl} \]In this reaction, two chlorine atoms are substituted with fluorine atoms, resulting in a compound with superior refrigerant properties, such as stability and non-flammability. Freon-12 was advantageous for its non-corrosiveness and minimal toxicity; however, like Freon-11, it also harms the ozone layer. As a result, its use has been significantly reduced in favor of more eco-friendly alternatives, aligning with international environmental agreements like the Kigali Amendment to the Montreal Protocol.