Question

Iron reacts with con. HCl and con. HтВВSOтВД , but it does not react with con.HNO3. Justify your answer with proper reasons.

Answer 1

Hydrochloric acid is just acidic. Nitric acid is both an acid and an oxidizer. If the copper has an oxide layer, the HCL will react with the oxide layer but it won’t make any more copper oxide to react with, so the reaction won’t proceeed. The Nitric acid on the other hand will continue to oxidize the copper and react with the copper oxide, until there’s no more copper to oxidize or there’s no more nitric acid left to do the oxidizing.

As an interesting aside, hydrochloric acid mixed with an oxidizer, even a weak oxidizer like household hydrogen peroxide, will vigorously attack copper.