Question

Name the gas evolves when aluminium reacts with nitric acid.Write the reaction involved.

Answer 1

In the reaction of aluminium with nitric acid, a gas evolved which is an oxide of nitrogen. It is used mainly for the production of fertilizers.

Complete step by step answer:
When aluminium reacts with nitric acid,nitrogen dioxide gas is evolved. Water is formed as a by product, the balanced chemical reaction occurs as follow:
${\text{Al}} + 6{\text{HN}}{{\text{O}}_3} \to {\text{Al}}{\left( {{\text{N}}{{\text{O}}_3}} \right)_3} + 3{\text{N}}{{\text{O}}_2} + 3{{\text{H}}_2}{\text{O}}$
Aluminium is a group 13 elements; it belongs to group number 13 and period number 3. Atomic number of Aluminium is 14 and the mass number is 27. The valency of Aluminium is 3. Nitric acid is a mineral acid and is highly corrosive in nature like other mineral acids. It is known as aqua fortis that is strong water. Oxidation state of nitrogen in nitric acid is plus 5 which is the highest in case of nitrogen because nitrogen has 5 electrons in its valence shell. Hence nitric acid is a very strong oxidizing agent. There is one electron on the nitrogen in nitrogen dioxide and hence it is a free radical. It has a reddish brown colour. It exists in equilibrium with its dimer that is dinitrogen tetroxide which is a colourless gas.
$NO_2$ is evolved when aluminium reacts with nitric acid.

Note:
Usually metals react with acids to form hydrogen gas but when metals are reacted with nitric acid then hydrogen gas is not liberated. The hydrogen formed oxidises to water. This is because nitric acid is a very strong oxidizing agent and it oxidises the hydrogen formed to water.