A current of 10.0 A needs to be passed for how many seconds to deposit 100 g of Al (molar mass = 27.0 g/mol) from molten Al₂O₃?

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Quizplus · Accepted Answer

To find the time required to deposit 100 g of Al, we use Faraday's laws of electrolysis. The amount of substance deposited (in moles) is given by $ \frac{It}{nF} $, where $ I $ is the current in amperes, $ t $ is the time in seconds, $ n $ is the number of electrons involved in the deposition of one mole of the substance (for aluminum, $ n = 3 $ since it's Al^3+), and $ F $ is Faraday's constant ($ 96485 \, C/mol $).First, calculate the moles of Al to be deposited: $ \frac{100 \, g}{27.0 \, g/mol} = 3.70 \, mol $.Then, rearrange the formula to solve for $ t $: $ t = \frac{nF \times \text{moles}}{I} $.Plugging in the values: $ t = \frac{3 \times 96485 \times 3.70}{10.0} = 1.07 \times 10^5 $ seconds.

A Current of 10