4al + 3o2 → 2al2o3 indicate how many electrons are transferred in the formation of one formula unit of product.

The balanced reaction is:

4 Al  +  3 O2  -->  2 Al2O3

Each Aluminum atom wants to lose 3 electrons to become isoelectronic with Oxygen. Each Oxygen on the other hand wants to gain 2 electrons. Since the reaction shows 6 Oxygen atoms in the product and each want to gain 2 electrons, therefore a total of 12 electrons are transferred. Since the problem ask for the electrons transferred per formula unit, hence:

6 electrons         (ANSWER)

i believe the answer is 5,000