What coefficients would balance the following equation?

__Al + __O2 → __Al2O3

Question 4 options:

(A) 2Al + 3O2 → 1Al2O3

(B) 2Al + 3O2 → 2Al2O3

(C) 3Al + 3O2 → 2Al2O3

(D) 4Al + 3O2 → 2Al2O3

The answer to your question is: Letter D.

Explanation:

To have a balanced reaction, the number of elements in the reactants, must be equal to the number of elements in the products.

So, count the number of elements in each side.

__Al + __O2 → __Al2O3

reactants elements products

1 Al 2

2 O2 3

It's unbalanced

Write a coefficient 4 in Al 4 Al + 3O2 → 2Al2O3

3 in O2

2 in Al2O3

And count again the number of elements

reactants elements products

4 Al 4

6 O2 6

Now, the reaction is balanced