A current is passed through a solution of a Al salt so that 96500 C of charge flows (F = 96 500 C/mol). What mass of Al is deposited at the cathode? (Al = 27)

Answer and explanation

Correct answer: B. 9 g

  1. Step 1: Moles of electrons mol.
  2. Step 2: Al needs 3 mol of electrons per mole of metal, so mass g.
Answer
9 g.
Why not the others: 27 g: the charge on the ion is ignored. 81 g: the charge number is multiplied instead of divided. 6.75 g: the wrong charge number is used.

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