Question

Nitrogen oxides like \(\mathrm{NO}_{2}\) and \(\mathrm{NO}\) are a significant source of acid rain. For each of these molecules write an equation that shows how an acid is formed from the reaction with water.

Short answer

When nitrogen dioxide (NO₂) reacts with water (H₂O), it forms nitrous acid (HNO₂) and nitric acid (HNO₃): \[ \mathrm{NO}_{2} + \mathrm{H}_{2}\mathrm{O} \rightarrow \mathrm{H}\mathrm{NO}_{2} + \mathrm{H}\mathrm{NO}_{3} \] For nitric oxide (NO), first, it reacts with oxygen (O₂) to form nitrogen dioxide (NO₂): \[ 2 \mathrm{NO} + \mathrm{O}_{2} \rightarrow 2 \mathrm{NO}_{2} \] Then, NO₂ reacts with water, forming nitrous acid (HNO₂) and nitric acid (HNO₃): \[ 2 \mathrm{NO} + \mathrm{O}_{2} + 2 \mathrm{H}_{2}\mathrm{O} \rightarrow 2 \mathrm{H}\mathrm{NO}_{2} + 2 \mathrm{H}\mathrm{NO}_{3} \]

Step-by-step solution

Identify the reactants

First, we need to identify the reactants involved in the reactions. The reactants are NO₂ and NO, as well as water (H₂O).

Determine the products for NO₂

When nitrogen dioxide (NO₂) reacts with water, it forms nitrous acid (HNO₂) and nitric acid (HNO₃). The chemical reaction is as follows: \[ \mathrm{NO}_{2} + \mathrm{H}_{2}\mathrm{O} \rightarrow \mathrm{H}\mathrm{NO}_{2} + \mathrm{H}\mathrm{NO}_{3} \] Now, we need to check if the equation is balanced. On the left-hand side, we have 1 nitrogen atom, 2 oxygen atoms, and 2 hydrogen atoms. On the right-hand side, we also have 1 nitrogen atom, 2 oxygen atoms, and 2 hydrogen atoms. Since the number of atoms on both sides of the equation is equal, the equation is balanced.

Determine the products for NO

When nitric oxide (NO) reacts with water, it forms nitrous acid (HNO₂). The chemical reaction is as follows: \[ \mathrm{NO} + \mathrm{H}_{2}\mathrm{O} \rightarrow \mathrm{H}\mathrm{NO}_{2} \] Now, we need to check if the equation is balanced. On the left-hand side, we have 1 nitrogen atom, 1 oxygen atom, and 2 hydrogen atoms. On the right-hand side, we have 1 nitrogen atom, 2 oxygen atoms, and 2 hydrogen atoms. The number of oxygen atoms is not equal on both sides, so we need to further investigate the possible products of this reaction or alternative reactants.

Consider an alternative reaction for NO

NO can also react with oxygen (O₂) before it reacts with water to form HNO₂ and HNO₃. The overall process can be divided into two steps: Step 1: NO reacts with O₂ to form NO₂: \[ 2 \mathrm{NO} + \mathrm{O}_{2} \rightarrow 2 \mathrm{NO}_{2} \] Step 2: NO₂ reacts with H₂O to form HNO₂ and HNO₃: \[ \mathrm{NO}_{2} + \mathrm{H}_{2}\mathrm{O} \rightarrow \mathrm{H}\mathrm{NO}_{2} + \mathrm{H}\mathrm{NO}_{3} \] By combining the two steps, we have the following: \[ 2 \mathrm{NO} + \mathrm{O}_{2} + 2 \mathrm{H}_{2}\mathrm{O} \rightarrow 2 \mathrm{H}\mathrm{NO}_{2} + 2 \mathrm{H}\mathrm{NO}_{3} \] Now, we check if the equation is balanced. On the left-hand side, we have 2 nitrogen atoms, 4 oxygen atoms, and 4 hydrogen atoms. On the right-hand side, we also have 2 nitrogen atoms, 4 oxygen atoms, and 4 hydrogen atoms. Thus, the equation is balanced.

Write the final equations

We found the corresponding balanced chemical equations for NO and NO₂ when reacting with water: For NO: \[ 2 \mathrm{NO} + \mathrm{O}_{2} + 2 \mathrm{H}_{2}\mathrm{O} \rightarrow 2 \mathrm{H}\mathrm{NO}_{2} + 2 \mathrm{H}\mathrm{NO}_{3} \] For NO₂: \[ \mathrm{NO}_{2} + \mathrm{H}_{2}\mathrm{O} \rightarrow \mathrm{H}\mathrm{NO}_{2} + \mathrm{H}\mathrm{NO}_{3} \]