To determine the amount of Faraday required to discharge 4.5 moles of Al3+ ions, it is essential to understand Faraday's laws of electrolysis and the concept of moles in chemistry.
When discharging Al3+ ions to form aluminum metal (Al), the reduction half-reaction involved is:
Al3+ + 3e- → Al
From this equation, it can be seen that 3 moles of electrons (e-) are required to discharge 1 mole of Al3+ ions to form 1 mole of aluminum metal.
A Faraday is the amount of electric charge carried by one mole of electrons. Therefore, 1 Faraday corresponds to the charge needed to discharge 1 mole of electrons.
Now, to discharge 4.5 moles of Al3+, we need:
4.5 moles of Al3+ × 3 moles of electrons (e-)/mole of Al3+ = 13.5 moles of electrons
Since each Faraday discharges 1 mole of electrons, 13.5 moles of electrons correspond to 13.5 Faradays of charge.
Hence, the amount of Faraday required to discharge 4.5 moles of Al3+ ions is 13.5 Faradays.