A chemist is purifying aluminum metal by the Hall process, in which Al³⁺ is reduced to (very pure) Al (molar mass = 27.0 g/mol) metal:
Al³⁺ + 3 e^-→Al If a current of 1.485 A is sent through the cell, how long will it take to produce 1.00 g of pure metal?

Question

Quizplus · Accepted Answer

The correct answer is A because the time required to produce 1.00 g of pure metal can be calculated using Faraday's law of electrolysis:$$t = \frac{m}{zIF}$$where:* t is the time in seconds* m is the mass of the metal produced in grams* z is the number of electrons transferred per mole of metal ions* I is the current in amperes* F is the Faraday constant (96,485 C/mol)In this case, z = 3 (since Al3+ ions are reduced to Al metal), I = 1.485 A, and m = 1.00 g. Substituting these values into the equation, we get:$$t = \frac{1.00 g}{3 	imes 1.485 A 	imes 96,485 C/mol} = 7.22 	imes 10^3 s$$

A Chemist Is Purifying Aluminum Metal by the Hall Process