[linjun]

if i put an iron nail into a solution of 40ml of 16.25%, 32.5% and 65% HNO3, will the result be same if i replace HNO3 wit HCl of the same strength? can anyone tell me why...

[wereworm73]

No, there will be some differences.  In hydrochloric acid, the nail dissolves to form iron(II) chloride, but with the strongly oxidizing nitric acid, a thin layer of iron(III) oxide forms on the nail, which can actually protect it from corrosion.