Question

How many coulomb of charge is required for deposition of 2/3 mole of al in electrolysis molten al2o3?

Answer 1

This question is derived from electrochemistry and it specifically determining the quantitative electrolysis.

What I mean by quantitative electrolysis is that from a given charge we determine the amount of substance deposited.

So going back to your question, you need to appreciate that 1 mole of electron requires 96500 coulomb of charge.

Thus Al³⁺ we have 3 electrons

so we say that 1 e⁻ = 96500 C

                         3 e⁻ = 3 x 96500

                                  =  289,500 C

                    therefore 2/3 x 289,500

                                    = 193,000 C.