Test: A piece of iron wire is placed in concentrated nitric acid for several minutes and doesn't react. The wire is removed and the acid is neutralized with an excess of sodium hydroxide solution. It is known from previous studies that iron (III) hydroxide forms a brown precipitate.

What is the observation expected if this hypothesis is correct: The iron wire only appears to not react with the concentrated acid. In fact the iron does react but does not produce gaseous products. Instead the products are all soluble (including iron nitrate). ???

Question

Test: A piece of iron wire is placed in concentrated nitric acid for several minutes and doesn't react. The wire is removed and the acid is neutralized with an excess of sodium hydroxide solution. It is known from previous studies that iron (III) hydroxide forms a brown precipitate. 

What is the observation expected if this hypothesis is correct: The iron wire only appears to not react with the concentrated acid. In fact the iron does react but does not produce gaseous products. Instead the products are all soluble (including iron nitrate). ???

zpupster · Answer

What is the observation expected--forms a brown precipitate, from your info.

anonymous · Answer

thankyou :) ...will the observation of the reaction still be the same with this initial information: When a clean iron wire is placed in dilute nitric acid a vigorous reaction occurs and a considerable volume of a brown gas is evolved. However, if the iron wire is placed in concentrated nitric acid scarcely any reaction is observed. 
The hypothesis in my first question was for this information, and then the experiment in my first question was carried out...with this information, is the observation you proposed still the same?