Chlorine gas is commonly used in the production of which of the following industrial compounds?

Analysis of the Question

The question asks for an industrial compound that requires chlorine gas as a raw material for its production. We need to evaluate each option based on industrial chemical processes.

Explanation of Concepts

• Chlorine Gas ($Cl_2$): A highly reactive halogen used extensively in the chemical industry for bleaching, water treatment, and the synthesis of organic and inorganic compounds.
• Chlorofluorocarbons (CFCs): These are organic compounds that contain carbon, chlorine, and fluorine. They are produced by replacing the hydrogen atoms in hydrocarbons (like methane or ethane) with chlorine and fluorine atoms through a process called halogenation. Chlorine gas is a primary reagent in this process.
• Methane ($CH_4$): This is a naturally occurring hydrocarbon (the main component of natural gas). It is a raw material, not a product made from chlorine.
• Ammonia ($NH_3$): Produced industrially via the Haber Process, which involves the reaction of nitrogen gas ($N_2$) and hydrogen gas ($H_2$). Chlorine is not involved.
• Ethanol ($C_2H_5OH$): Produced industrially by the hydration of ethene or the fermentation of sugars. Chlorine is not a reactant in these processes.

Step-by-Step Solution

1. Evaluate Option A: CFCs (e.g., $CCl_2F_2$) are synthesized by reacting hydrocarbons with chlorine and fluorine. Chlorine gas is essential for the chlorination step.
2. Evaluate Option B: Methane is a starting material (a reactant), not a product of a process using chlorine.
3. Evaluate Option C: Ammonia is synthesized from Nitrogen and Hydrogen. Chlorine is not part of the Haber process.
4. Evaluate Option D: Ethanol is produced from ethene or glucose. Chlorine is not used in these production pathways.

Since chlorine is a fundamental component in the synthesis of CFCs, Option A is the correct industrial application.

Conclusion

The production of Chlorofluorocarbons (CFCs) relies on the substitution of hydrogen atoms in alkanes with chlorine atoms, making chlorine gas a vital industrial input for this process.

Exam Tip

When you see questions about industrial chemistry, remember the "Haber-Contact-Solvay" trio:

• Haber Process: Ammonia ($NH_3$)
• Contact Process: Sulfuric Acid ($H_2SO_4$)
• Solvay Process: Sodium Carbonate ($Na_2CO_3$) If the question asks about chlorine, look for keywords like "bleaching," "PVC," or "CFCs."