Question

“Nitric oxide reacts with oxygen to form reddish brown nitrogen dioxide gas”
A) $2NO + {O_2} \to 2N{O_2}$
B) ${N_2}O + {O_2} \to N{O_2} + NO$
C) $NaN{O_3}\xrightarrow{{heat}}2NaN{O_2} + {O_2}$
D) $2N{O_3} + {O_2} \to 2N{O_2} + 2{O_2}$

Answer 1

The answer for this question lies in finding the molecular formulas for the reactants and products of the given reaction. The oxidation of nitric oxide is giving nitrogen dioxide gas whose molecular formula is $N{O_2}$

Complete step-by-step answer: Given to us is a reaction between nitric oxide and oxygen to give nitrogen dioxide gas which is reddish brown in color. This reaction is an oxidation reaction.
Nitric oxide is being oxidized to form nitrogen dioxide which means that oxygen atoms are being add up to the reactant molecule to form nitrogen dioxide i.e. $N{O_2}$
This means that the reactant molecule should have less oxygen atoms when compared to nitrogen dioxide. This means that the reactants can either be $NO$ or ${N_2}O$
But we already know that ${N_2}O$ is Dinitrogen Oxide and this means that nitric oxide is $NO$ . This compound is also known as Nitrogen Monoxide.
Therefore our given reaction would be $NO + {O_2} \to N{O_2}$
In this equation, there are three oxygen atoms on the reactants side and only two oxygen atoms on the products side. Hence, we need to balance this reaction.
The balanced reaction can be written as $2NO + {O_2} \to 2N{O_2}$

Therefore the correct answer is option B.

Note: In the above reaction two moles of nitric oxide is being oxidized with one mole of oxygen to form two moles of nitrogen dioxide. These molecules have been identified as follows.
Nitric oxide or Nitrogen monoxide: $NO$
Nitrogen dioxide: $N{O_2}$