Iron with Steam Chemical Equation 

3Fe (Iron) + 4H₂O (Water) → Fe₃O₄(Iron(II,III) Oxide) + 4H₂ (Hydrogen Gas)

Calcium with Water 

Metal + Steam → Metal Hydroxide + Hydrogen Gas Ca + 2H₂O → Ca(OH)₂ + H₂

Potassium with Water 

Potassium reacts violently with cold water to form potassium hydroxide. During the process, much heat is released; the hydrogen gas generated caught fire and rapidly burned.

2K + 2H₂O → 2KOH + H₂ + Heat