Answer:
A. 6 water molecules, hydrogen is limiting.
Step-by-step explanation:
For a molecule of water, you need 2 hydrogen atoms and 1 oxygen atom. Therefore, if there is 6 molecules of hydrogen and 6 molecules of oxygen, there are 12 atoms of hydrogen and 12 atoms of oxygen. You need 2 of hydrogen so you will divide 12 by 2. 12-2=6. You need only 1 atom of oxygen so it will stay as 12. The limiting reactant is hydrogen because there are only 6 while there are 6 atoms of oxygen remaining. There will only be 6 water molecules formed due to the insufficient amount of hydrogen.