H2 could be produced by electrolysis of water or by reaction of Zn metal with acid (HCl or H2SO4).
2H2O -> 2H2 + O2
Zn + 2HCl -> ZnCl2 + H2
Once H2 gas is collected, it has to be somehow bubbled through water, and then the resulting water should show a negative ORP. This water is H2 rich, and stronly anti-oxidant. But H2 will evaporate and the water will become H2 poor in short time.
Need some experimentation here. Any Science volunteers?