Question

What is the concentration of nitrate ion in a solution that contains $ 0.900\;M $ aluminium nitrate?

Answer 1

Hint: Aluminium nitrate is a white, crystalline solid which is water soluble salt of aluminium and nitric acid. They are odourless, colourless and used in tanning leather and as an antiperspirant, nitrating agent and corrosion inhibitor.

Complete answer:
We cannot manufacture Aluminium nitrate, by the reaction of aluminium with concentrated nitric acid, as the aluminium forms a passivation layer. Aluminium nitrate is synthesized by the reaction of nitric acid with aluminium $ \left( {III} \right) $ chloride. In this reaction nitrosyl chloride is produced which is a by-product; it bubbles out of the solution as a gas. The salt can be made by reacting nitric acid with aluminium hydroxide.
 Aluminium nitrate is a strong oxidizing agent. It is mostly used in the laboratory in the chemical reaction. The hydrated and non-hydrated aluminium nitrates have many applications. Aluminium nitrate used in petroleum refining, dyeing and leather tanning. These salts also used to form alumina which is used for making insulating papers.
The chemical formula of aluminium nitrate is $ Al{\left( {N{O_3}} \right)_3} $ . When aluminium nitrate dissociates it gives aluminium ion and nitrate ion. The chemical equation this reaction is:
 $ Al{\left( {N{O_3}} \right)_3} \to A{l^{3 + }} + 3N{O_3}^ - $
By the above reaction we notice that the one mole of aluminium nitrate yields three moles of nitrate. So, we have:
 $ \Rightarrow 0.9\;mol\;of\;Al{\left( {N{O_3}} \right)_3} \times \dfrac{{3\;mol\;of\;NO_3^ - }}{{1\;mol\;of\,Al{{\left( {N{O_3}} \right)}_3}}} $
 $ \Rightarrow 2.7\;mol\;of\;NO_3^ - $
Thus, the concentration of nitrate ion is $ 2.7\;mol $ .

Note:
Aluminium nitrate are non-combustible compounds but they can help in fasten burning of the combustible materials. If large amounts of combustible materials are involved then an explosion can occur. Moreover prolonged exposure to heat, can lead to an explosion.