Often in the lab, diluted sulphuric acid (H2SO4) is used for dissolving Iron(II) Sulphate (FeSO4.7H2O) cystals. Since this Iron(II) salt is water soluble, why isn't distilled water preferred?
(1) O2 + 4H+ + 2e <-> 2 H2O E=+1.23V
(2) O2 + 2H2O + 4e <-> 4OH- E=+0.40V
With reference to the equations above, an acidic medium would favour the forward reactions of both equilibria. Hence, Iron(II) should have a higher tendency to be oxidised to Iron(III) in an acidic medium. I would think that an acidic envionment will contribute to the relative instability of iron(ii) ions in solution. Hence, dilute sulphuric acid should not be employed.
Someone please enlighten. Thank you alot.