Question

Which is an ozonide?
(A) $K{{O}_{3}}$
(B) \[N{{H}_{4}}{{O}_{3}}\]
(C) $C{{r}_{2}}{{O}_{3}}$
(D) both (a) and (b)

Answer 1

Hint: Ozonides are highly unstable compounds. The main use of ozonides is to produce nascent oxygen which is used in many chemical reactions for oxidation. Hence the compound must have an unstable configuration which can decompose even at low temperatures.

Complete step by step answer:
Ozonides are unstable, highly reactive polyatomic anion ${{O}_{3}}^{-}$ considered analogous to ozone and several classes of peroxide that are formed by the reaction of ozone with an unsaturated compound.
Ozonides are of two types namely, ionic and organic ozonides:
-Inorganic or ionic ozonides are dark red ionic compounds containing the reactive ${{O}_{3}}^{-}$ anion. The anion has a bent shape like that of the ozone molecule.
Inorganic ozonides are formed by burning potassium, rubidium, caesium etc in presence of ozone.

\[Cs{{O}_{3}}+\text{ }\!\![\!\!\text{ }{{\left( C{{H}_{3}} \right)}_{4}}N]\left[ {{O}_{2}} \right]\text{ }\to \text{ }Cs{{O}_{2}}+\text{ }\!\![\!\!\text{ }{{\left( C{{H}_{3}} \right)}_{4}}N]\left[ {{O}_{3}} \right]\]

-Organic ozonides also referred to as molozonides are typically formed by the addition reaction between ozone and alkenes. They are more explosive than organic peroxides.
They are highly unstable and readily convert to stable trioxolane ring structure which further decompose to give aldehydes and ketones.

Let us now try to find then ozonides in the given options:
-In $K{{O}_{3}}$ , K shows +1 charge as it belongs to group 1 of the periodic table. The negative charge is shared by 3 oxygen atoms like the ozonide ion. Hence $K{{O}_{3}}$is an ozonide.
- In \[N{{H}_{4}}{{O}_{3}}\], the cation is \[N{{H}_{4}}^{+}\]with a charge of +1. The negative charge is once again shared among 3 oxygen atoms making it an ozonide. Hence \[N{{H}_{4}}{{O}_{3}}\] is an ozonide.
- In $C{{r}_{2}}{{O}_{3}}$, the stable oxidation state of Cr is +3, the total positive charge is +6. Oxygen exists in the oxidation state of -2 to balance the positive charge. Hence $C{{r}_{2}}{{O}_{3}}$ is not an ozonide.
So, the correct answer is “Option C”.

Note: At time students check only compounds if it is an ozonide, and mark only one compound as the answer. However, when you check all the three compounds, you will find that there are two ozonide compounds and hence the correct answer is both the compounds which are mentioned in option (C).