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

"hydrogen bonding is the attraction of h atoms in the water molecule (slight + charge) to o atoms in a neighboring water molecule (slight - charge); it is a weak interatomic force. but it is still strong enough to the water molecules "stick" together."