Question

The formula of zinc nitrate is:
(A) $Zn{{(N{{O}_{2}})}_{3}}$
(B) $Zn{{(N{{O}_{2}})}_{2}}$
(C) $Zn{{(N{{O}_{3}})}_{3}}$
(D) $Zn{{(N{{O}_{3}})}_{2}}$

Answer 1

Hint: Zinc nitrate is an inorganic compound. In zinc nitrate, zinc is the cation and nitrate is the anion. There are two nitrate ions because the charge on the zinc is +2 and the charge on the nitrate ion is -1.

Complete step by step solution:
The formula of zinc nitrate is $Zn{{(N{{O}_{3}})}_{2}}$ and it is an inorganic chemical compound. The valency of the zinc is +2 and the valency of the nitrate ion is -1, that’s why in the zinc nitrate formula there are two nitrate molecules.
Zinc nitrate is mostly found in the hexahydrate form having formula $Zn{{(N{{O}_{3}})}_{2}}.6{{H}_{2}}O$ and it is a white crystalline solid having the high property of attracting water molecules. Zinc nitrate is a very soluble compound i.e., it is soluble in both water and alcohol.
The molar mass of zinc nitrate $Zn{{(N{{O}_{3}})}_{2}}$ is $189.36\text{ g/mol}$ and the molar mass of its hexahydrate form is $297.49\text{ g/mol}$.
The density of hexahydrate form of zinc nitrate is $2.065\text{ g/c}{{\text{m}}^{3}}$.
The melting point of anhydrous zinc nitrate is ${{110}^{\circ }}C$and the melting point of hexahydrate form of zinc nitrate is ${{36.4}^{\circ }}C$.
The boiling point is ${{125}^{\circ }}C$ which means that it decomposed at this temperature.
It is used as an oxidant and it may even explode on heating. It is a non-flammable substance.
Zinc nitrate can be prepared by treating zinc with dilute nitric acid. The reaction is given below:
$Zn+2HN{{O}_{3}}\to Zn{{(N{{O}_{3}})}_{2}}+{{H}_{2}}$

So, the correct answer is an option (D) $Zn{{(N{{O}_{3}})}_{2}}$.

Note: Zinc nitrate is mostly used in the laboratory for the preparation of coordination polymers but it doesn't have any specific large scale industrial application. Zinc nitrate converts into zinc oxide, nitrogen oxide, and oxygen when heated at high temperatures.
$2Zn{{(N{{O}_{3}})}_{2}}\to 2ZnO+4N{{O}_{2}}+{{O}_{2}}$