Is there enough oxygen in the air with a volume of 200 dm3 for the complete oxidation of hydrogen sulfide

Is there enough oxygen in the air with a volume of 200 dm3 for the complete oxidation of hydrogen sulfide with a volume of 40 dm3 to sulfur oxide (IV)?

Given:
V (air) = 200 dm3 = 200 l
V (H2S) = 40 dm3 = 40 l
φ (O2) = 21%
Vm = 22.4 l / mol
Find: V (O2) – Enough?
Decision:
1) 3O2 + 2H2S => 2SO2 + 2H2O;
2) V (O2) = φ (O2) * V (air) / 100% = 21% * 200/100% = 42 liters;
3) n (O2) = V (O2) / Vm = 42 / 22.4 = 1.88 mol;
4) n (H2S) = V (H2S) / Vm = 40 / 22.4 = 1.79 mol;
5) n required (O2) = n (H2S) * 3/2 = 1.79 * 3/2 = 2.69 mol;
6) n (O2) <n req. (O2).
Answer: The volume of O2 (from 200 dm3 of air) will be insufficient for complete oxidation.