If 1.5 moles of H2 reacts with 1.0 moles of oxygen, which would be the limiting reactant?

Answer 1

2H2 + O2 ==>2H2O
1.5 mols H2 with excess O2 will produce 1.5 mols H2O
1 mols O2 with excess H2 will produce 2 mols H2O
In limiting reagent problems the small number always wins because you can produce ONLY the smallest amount and have some of the excess reagent left over un-reacted. So H2 is the limiting reagent in this reaction.