Nitric acid and magnesium reaction, slow gas production

[mbeaumont99]

Homework Statement

I need to work out what is happening with the above reaction. Why is my data showing a very slow hydrogen gas production rate (if it even is hydrogen gas), in fact, even slower than the production of hydrogen gas from the reaction of magnesium and ethanoic acid. All acids used were 1 mol/L. Magnesium ribbon used had (roughly) the same surface area and mass.

Homework Equations

Mg(s) + 2H+(aq) → Mg2+(aq) + H2(g)

The Attempt at a Solution

With nitric acid being a strong acid and magnesium being a reactive metal surely the hydrogen gas production would be very high, just like that of HCl with magnesium. Magnesium is a strong reductant and nitric acid is a strong oxidant, could this be what is causing a problem with the reaction. I read on wiki that this COULD be due to the reaction producing nitrogen oxide (+1, +2, or +4 oxidation states for nitrogen - different sources giving different nitrogen oxides). Why would nitric acid and magnesium reacting produce a different gas to hydrogen at such a slow rate. I would really appreciate help with determining why this outcome has occurred. Thanks

 

[Borek]

Perhaps hydrogen is reacting with the nitric acid reducing it to ammonia.