Page 37 - Curriculum Visions Dynamic Book

Water bath keeps the nitric acid cool.
The products of nitric acid
Nitric acid reacts with a wide variety of substances. The reaction oxidises the other reagent, and reduces the nitric acid to a range of products from nitrogen dioxide to ammonia.
Very dilute nitric acid reacts with reactive metals such as magnesium to produce hydrogen and nitric oxide. Less reactive metals such as zinc and iron produce ammonia. Poorly reactive metals such as copper and mercury result in the production of nitric oxide.
Concentrated nitric acid produces nitrogen dioxide instead of nitric oxide. The difference is caused
by the fact that concentrated
nitric acid is able to oxidize the nitric oxide released, thus forming nitrogen dioxide.
A few metals, such as gold
and platinum, are not affected by nitric acid, while others, such as aluminium, do not react because they are protected by their
oxide coating.
fuming: an unstable liquid that gives off a gas. Very concentrated acid solutions are often fuming solutions.
oxidising agent: a substance that removes electrons from another substance (and therefore is
itself reduced).
reagent: a starting material for a reaction.
vapour: the gaseous form of a substance that is normally a liquid. For example, water vapour is the gaseous form of liquid water.
Fuming nitric acid
Also... Making nitric acid industrially
Ammonia (along with oxygen) is used to make nitric acid. However, ammonia and oxygen do not combine easily, and a three stage process has to be employed.
Stage 1: oxygen and ammonia combine to make nitric oxide (NO). This is achieved at high temperatures and uses a catalyst of platinum gauze. The reaction takes place in less than one-thousandth of a second.
Stage 2: Nitric oxide and oxygen are combined to produce nitrogen dioxide (NO2).
Stage 3: Nitrogen dioxide is absorbed into water to make nitric acid.
The whole process is called the Ostwald process, and it shows that,
on some occasions, in practical terms what appears to be a rather simple reaction is in fact quite difficult to achieve.
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