I just went though a reaction wherein hydrogen gas is liberated and hence restricts the product formed to ferrous and not ferric salt. I just want to know how H2 gas gets its reducing property? It has a moderate bond strength also if I am not wrong.
Iron on reaction with HCl forms Fe(II) salts and not Fe(III) salts because even if Fe(+3) is formed, as we can see in electrochemical series Fe(+2) will be favoured ie. H2 which gets can reduce Fe(+3) to Fe(+2). So thermodynamically Fe(+2) salt is favoured. If you want to make Fe(+3) salt then you can react Fe and Cl2 directly.
How H2 gets its reducing property?
H2 gas will react with FeCl3 to form FeCl2 and HCl. I don't know the exact mechanism but it can be explained well on the basis thermodynamic data available.