Which sequence ranks the chemical reactions in order from fastest to slowest

4 and 3 are the correct coefficients

Explanation:

In order to do so, let's write the equation again:

Sb + O₂ > Sb₄O₆

Now, before we even think to balance this, we need to know the priority order of balancing which is Metals > Non metals > Hydrogen and oxygen

In this equation we have only metals and oxygen, so we will begin with the metal.

In the reactant we have 1 Sb atom and in the product we have 4 (Sb4), so, all we need to do there, is to put a number 4 as coefficient next to the Sb in the reactant. You should note that to balance any atom in a chemical equation, you are only permitted to put numbers as coeffcients and behind the atom or molecule. You should never put those numbers as subscripted because it's wrong.

Putting the 4 in the equation we have then:

4Sb + O₂ > Sb₄O₆

Now the Sb is balanced, let's go with the oxygen. In reactans we have 2 O while in products we have 6, so, to balance this, we can put a 3 behing the Oxygen in the reactant. In that way, the 3 will multiply the 2 of the atom, and the total would be 6 and it will be completely balanced so:

4Sb + 3O₂ > Sb₄O₆