A + B = Products
This is the correct mechanism.
A control group is the comparison group that helps to "make sure your experiment works." A control group is separated from the rest of the experiment and nothing happens to it kinda like a controlled variable. Controlled variables are the variables in a experiment that remains the same for example a temperature, time, type of products, etc..
Hope this helps!
Hydrogen + oxygen -> water
2H2 + O2 -> 2H2O (balanced)
2 moles of hydrogen gas will react with 1 mole of oxygen to produce 2 moles of water.
following that ratio, 0.734 mole of oxygen must need 0.734 × 2 moles of hydrogen to fully react.
answer is 1.468 moles of hydrogen.