Conversion of Al2O3 to anhydrous AlCl3

To convert Al2O3 (aluminum oxide) to anhydrous AlCl3 (aluminum chloride), the most suitable method is option 'B': a mixture of Al2O3 and carbon in dry Cl2 gas. This method involves a chemical reaction that allows the conversion to take place.

Explanation:

The reaction can be represented by the following equation:

2 Al2O3 + 3 C + 3 Cl2 → 4 AlCl3 + 3 CO2

Now, let's break down the process and understand why this option is the correct answer.

Mixture of Al2O3 and Carbon:
When a mixture of Al2O3 and carbon (C) is heated, the carbon acts as a reducing agent. It reacts with the oxygen from the Al2O3, resulting in the formation of carbon monoxide (CO) and aluminum metal (Al).

Al2O3 + 3 C → 2 Al + 3 CO

Reaction with Dry Cl2 Gas:
In the next step, the aluminum metal formed in the previous reaction reacts with dry Cl2 gas (chlorine gas). This reaction forms aluminum chloride (AlCl3), which is anhydrous (meaning it does not contain any water molecules).

2 Al + 3 Cl2 → 2 AlCl3

Overall Reaction:
Combining the two reactions, we can write the overall reaction as follows:

2 Al2O3 + 3 C + 3 Cl2 → 4 AlCl3 + 3 CO2

This equation represents the conversion of aluminum oxide (Al2O3) to anhydrous aluminum chloride (AlCl3) using a mixture of Al2O3 and carbon in dry Cl2 gas.

Why Option B:
Among the given options, option 'B' is the correct answer because it involves the appropriate combination of reactants and conditions to obtain anhydrous aluminum chloride. The other options do not provide the necessary reactants or conditions for the desired reaction to occur.

Conclusion:
The conversion of Al2O3 to anhydrous AlCl3 involves heating a mixture of Al2O3 and carbon in dry Cl2 gas. This method allows for the reduction of Al2O3 and subsequent reaction with chlorine gas to form anhydrous aluminum chloride. This reaction is represented by the equation 2 Al2O3 + 3 C + 3 Cl2 → 4 AlCl3 + 3 CO2.