Answer:
H2 is the limiting reactant.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
2H2 + O2 —> 2H2O
Next, we shall determine the limiting reactant as follow:
From the balanced equation above,
2 moles of H2 reacted with 1 mole of O2.
Therefore, 4 moles of H2 will react with = (4 x 1)/2 = 2 moles of O2.
From the calculations made above, we can see that only 2 moles out of 3 moles of O2 given, is needed react completely with 4 moles of H2.
Therefore, H2 is the limiting reactant and O2 is the excess reactant.