Question

The mixed anhydride of nitrogen is:
(A) ${{N}_{2}}{{O}_{2}}(2NO)$
(B) ${{N}_{2}}{{O}_{4}}(2N{{O}_{2}})$
(C) ${{N}_{2}}{{O}_{5}}$
(D) ${{N}_{2}}{{O}_{3}}$

Answer 1

Hint: Anhydrides is a chemical compound which is obtained by the elimination of water from another compound. There are different oxides of nitrogen, they are mixtures of nitrogen gas and oxygen gas.

Complete step by step solution:
Different oxides of nitrogen are present in which two of them are the most toxic compounds. The first one is nitric oxide and the second one is nitrogen dioxide. There are some other gases which belong to the group of nitrogen monoxides, these gases are dinitrogen trioxide, nitrous oxide and dinitrogen pentoxide.
Mixed anhydride or double acid anhydride is the compound which reacts with water to form two acid anhydride. The two oxides of nitrogen are the acid anhydrides so they react with water to form two oxy acids containing nitrogen or we can say that when nitrogen dioxide is added to water there is no acid where the oxidation state of nitrogen is equal to +4 so nitrogen dissociates into two oxyacids.
The reaction involved is shown below:
\[2N{{O}_{2}}+{{H}_{2}}O\to HN{{O}_{3}}+HN{{O}_{2}}\]
When nitrogen dioxide is added to water there is no acid where the oxidation state of nitrogen is equal to +4 so nitrogen dissociates into two oxyacids.

Hence the correct answer is option (B) i.e. the mixed anhydride of nitrogen is ${{N}_{2}}{{O}_{4}}(2N{{O}_{2}})$

Note: If an anhydride produces a base after the addition of water to it then the anhydride will be a basic anhydride. The anhydride of inorganic acids are usually the oxides of non- metallic elements and the anhydrides of the organic acids contain carbonyl groups in them.