Determining the Formation of a Sulfur Oxide
Giovanna conducted an experiment combining gaseous sulfur in air. The reaction was conducted in a fume hood for safety reasons.

Three possible reactions for this experiment are:

Reaction I
S + O2 → SO2

Reaction II
[?]S + [?]O₂ → [?]SO3

Reaction III
5S + 3N2 → S5N6

What is the correct balanced equation for Reaction II?
2S + 3O2 → 2SO3
S + O3 → SO3
S + O2 → SO3