Pure hydrogen and oxygen gas is required for making water molecules by mixing both gases with the help of heat source, it is highly dangerous to prepare oneself, kindly seek your lab assistant (or) incharge for this experiment.
Theoretically, this is possible, but it would be an extremely dangerous process, too. To create water, oxygen and hydrogen atoms must be present. Mixing them together doesn't help; you're still left with just separate hydrogen and oxygen atoms.
Sayesha answered this
It is extremely easy to make water from hydrogen gas and oxygen gas. simply mix the two gases together, add a spark or sufficient heat to provide an activation energy to start the reaction.