When a concentrated solution of AlCl3 is electrolyzed, aluminum metal is deposited at the cathode while chlorine gas is evolved at the anode.
The overall reaction can be represented as:
2AlCl3 (l) -> 2Al (s) + 3Cl2 (g)
At the cathode:
Al3+ (aq) + 3e- -> Al (s)
At the anode:
2Cl- (aq) -> Cl2 (g) + 2e-
The electrolysis of concentrated AlCl3 solution is typically carried out using an inert electrode such as graphite or platinum. The electrolysis process requires a high voltage to overcome the high melting point of aluminum and the high reactivity of chlorine gas.
Overall, the electrolysis of concentrated AlCl3 solution is an important industrial process for the production of aluminum metal, which is widely used in various industries.
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Google Gemini AI
more than 4 weeks ago
Electrolysis of Concentrated AlCl3 Solution
Reaction:
2AlCl3(l) → 2Al(s) + 3Cl2(g)
Conditions:
- Concentrated AlCl3 solution in a molten state (~150-200°C) - Inert electrodes (e.g., graphite or platinum) - High temperature
Mechanism:
1. Ionization of AlCl3: AlCl3 dissociates into Al3+ and Cl- ions. 2. Reduction at cathode: Al3+ ions migrate to the cathode and gain electrons, forming aluminum metal: Al3+ + 3e- → Al(s) 3. Oxidation at anode: Cl- ions migrate to the anode and lose electrons, forming chlorine gas: 2Cl- → Cl2(g) + 2e- 4. Formation of aluminum metal: The reduced aluminum ions solidify on the cathode. 5. Formation of chlorine gas: The oxidized chlorine gas bubbles out of the solution.
Industrial Significance:
The electrolysis of concentrated AlCl3 solution is the primary method for the production of aluminum metal. Aluminum is an important lightweight metal used in various industries, including aerospace, automotive, construction, and packaging.
Electrode Material:
Graphite electrodes are commonly used because they are chemically inert and resistant to corrosion. Platinum electrodes can also be used, but they are more expensive.
Temperature Control:
Maintaining a high temperature is crucial to keep the AlCl3 solution molten and enhance ion mobility. The temperature is typically controlled by external heating or by passing an electric current through the solution.
Byproducts:
Besides aluminum metal and chlorine gas, the electrolysis process can also produce small amounts of hydrogen gas and hydrogen chloride gas. These byproducts are typically removed by scrubbing or filtering.