H₂ is the limiting reactant.
Explanation:
H₂ reacts with O₂
The reaction would be
2H₂ + O₂ → 2H₂O
According to the balanced equation, 2 moles of H₂ reacts with 1 mole of O₂ to form 2 moles of H₂O.
The ratio of usage of H₂ and O₂ is 2 : 1 respectively
If 3 moles of H₂ and 2 moles of O₂ are present then:
3 moles of H₂ would require 1.5 moles of O₂ ( 2 : 1 of H₂ and O₂ )
Out of 2 moles of O₂, 1.5 moles would be used and 0.5 mole would be in excess.
Therefore, H₂ is the limiting reactant as the number of moles of H₂ are not enough to use all the O₂.