Question

What is the property of nitric acid which allows it to react with copper?

Answer 1

Hint: Nitric acid acts as a strong oxidizing agent. Oxidizing agent is defined as those substances which have the capability to oxidize other substances by accepting electrons. Copper reacts with nitric acid and produces cupric nitrate and evolves nitrogen dioxide gas.

Complete answer:
The chemical formulas of copper and nitric acid are $ Cu $ and $ HNO_3 $ . $ HNO_3 $ acts as a strong oxidising agent which oxidizes copper metal $ (Cu) $ into cupric ions $ (C{{u}^{2+}}) $ . The redox reaction takes place between $ Cu $ and $ HNO3 $ which is given by the following equation:
 $ Cu + 2HNO_3 \to Cu(NO_3)_2 + 2 NO_2 + 2H_2O $
From the above balanced chemical equation, we conclude that copper undergoes oxidation via loss of two electrons and produces cupric nitrate $ (Cu(NO_3)_2) $ . In contrast, nitric acid undergoes reduction via gain of two electrons and produces nitrogen dioxide $ (NO_2) $ .
Therefore, the oxidizing property of nitric acid allows it to react with copper.

Additional Information:
Oxidation and reduction processes take place simultaneously and that’s why such types of reactions are named as redox reactions. In redox words, “re” represents reduction and “ox” represents oxidation. The reduced product of the above reaction i.e. nitrogen dioxide is a brown colour gas which is poisonous and has irritating odour. Besides the oxidizing agent property, nitric acid is a chief reagent used for nitration purposes. For example: nitration of benzene takes place in the presence of concentrated nitric acid $ (HNO_3) $ and concentrated sulphuric acid $ (H_2SO_4) $ .

Note:
It is important to note that nitric acid acts as a strong oxidizing agent. This oxidizing property of nitric acid allows it to react with copper. A redox reaction takes place between $ Cu $ and $ HNO_3 $ which ultimately produces cupric nitrate $ (Cu(NO_3)_2) $ and hydrogen gas $ (H_2) $ as products.