Answer:
D. Al(s) + O₂(g) → Al₂O₃(s)
Explanation:
Aluminum is a solid metal, so it is written as Al(s).
Oxygen is a diatomic gas, so we write this compound as O₂(g).
Aluminum oxide has the formula Al₂O₃ because in oxides the oxidation number of oxygen atom is -2 and for aluminum, the oxidation number is 3. Thus, we write this compound as Al₂O₃(s).
Now, we have to found the chemical equation in which the reactants (left side) are Al(s) and O₂(g) while the product (right side) is Al₂O₃(s). From the options, we can see that the correct is (D):
Al(s) + O₂(g) → Al₂O₃(s)
