Answer
2 L of hydrogen react with 1 L of oxygen
4 mol of hydrogen reacts with 2 moles of oxygen.
Step-by-step explanation
In the equation: 2H2 + O2 → 2H2O
All that applies to the equation are:
2 L of hydrogen react with 1 L of oxygen
4 mol of hydrogen reacts with 2 moles of oxygen.