Question

aluminum plating is sometimes used to reduce corrosion in materials exposed to the outdoors. a section of a metal roof is plated with aluminum for a builder.
a current is applied to an aluminum sulfate solution. how many moles of electrons are transferred during the reduction of aluminum?
? mole e⁻

Explanation:

Step1: Determine the ion and its charge

Aluminum in aluminum sulfate ($\ce{Al2(SO4)3}$) exists as $\ce{Al^{3+}}$ ions.

Step2: Write the reduction half - reaction

The reduction half - reaction for aluminum is $\ce{Al^{3+} + 3e^-
ightarrow Al}$. From this half - reaction, we can see that for each mole of $\ce{Al^{3+}}$ that is reduced to aluminum metal, 3 moles of electrons are transferred. Since we are considering the reduction of 1 mole of aluminum (from $\ce{Al^{3+}}$), the number of moles of electrons transferred is 3.

Answer:

3