* Iron(II) chloride: FeCl₂

* Iron(III) chloride: FeCl₃

Hydrogen is simply H₂.

So, depending on which iron chloride you're talking about, the chemical symbols would be:

* FeCl₂ + H₂ (Iron(II) chloride plus hydrogen)

* FeCl₃ + H₂ (Iron(III) chloride plus hydrogen)