Question

26 Given the balanced equation representing a reaction:4Al(s) + 3O2(g) ==> Al2O3(s)

As the aluminum loses 12 moles of electrons, the oxygen
(1) gains 4 moles of electrons
(2) gains 12 moles of electrons
(3) loses 4 moles of electrons
(4) loses .12 moles of electrons

Answer 1

(2) gains 12 moles of electrons, easy, because it must retain the same mass in a balanced equation, so if there is no exterior mention of any electrons, such as the notation +12e-, than we must assume that the Oxygen took it at any rate.