Understanding Faraday's Laws of Electrolysis
To determine the number of Faraday required to deposit 1 gram equivalent of aluminum from an AlCl3 solution, we first need to understand the electrochemical process involved in the deposition.
1. Electrochemical Reaction
- The reaction for the electrolysis of aluminum chloride (AlCl3) can be summarized as:
- Al³⁺ + 3e⁻ → Al
- This indicates that one mole of aluminum ions (Al³⁺) requires three moles of electrons (3e⁻) for deposition.
2. Equivalent Weight of Aluminum
- The equivalent weight of aluminum (Al) can be calculated as follows:
- Atomic weight of Aluminum (Al) = 27 g/mol.
- Since aluminum has a valence of 3, the equivalent weight is:
- Equivalent weight = Atomic weight / Valence
- Equivalent weight = 27 g / 3 = 9 g/equiv.
3. Calculating Faraday
- One Faraday (F) is defined as the charge required to deposit one equivalent of a substance during electrolysis.
- To deposit 1 gram equivalent of aluminum, we need to consider:
- 1 gram equivalent of Al = 9 g (as calculated).
- For the deposition of 1 gram equivalent of aluminum:
- Required charge = 3 Faraday (since 3 electrons are needed for 1 Al³⁺).
Conclusion
- Therefore, the number of Faraday required to deposit 1 gram equivalent of aluminum from the solution of AlCl3 is 3 Faraday.
This result underscores the relationship between charge, mass, and electrochemical equivalents in the process of electrolysis.