Problem 45 - Chemistry: An Atoms-Focused Approach

Question

A \(1.0 M\) aqueous solution of \(\mathrm{HNO}_{3}\) is a much better conductor of electricity than is a \(1.0 M\) solution of \(\mathrm{HNO}_{2}\) Explain why.

Step-by-Step Solution

Answer

Answer: A 1.0 M aqueous solution of HNO3 is a better conductor of electricity than a 1.0 M solution of HNO2 because HNO3 is a strong acid that fully dissociates/ionizes in water, resulting in more ions in the solution, which are responsible for conducting electricity.

Step 1: Understand the difference between strong and weak acids

Both HNO\(_3\) and HNO\(_2\) are acids, but they have different characteristics. \(\mathrm{HNO}_3\) is a strong acid, meaning it completely dissociates/ionizes in water. On the other hand, \(\mathrm{HNO}_2\) is a weak acid, meaning it partially dissociates/ionizes in water. The difference in dissociation/ionization will affect the number of ions in the solution, which affects the ability to conduct electricity.

Step 2: Write the ionization equations for both acids

Let's write the ionization equations for both acids in water. For \(\mathrm{HNO}_3\), as a strong acid: \(\mathrm{HNO}_3 \to \mathrm{H}^+ + \mathrm{NO}_3^-\) For \(\mathrm{HNO}_2\), as a weak acid: \(\mathrm{HNO}_2 \leftrightarrows \mathrm{H}^+ + \mathrm{NO}_2^-\)

Step 3: Analyze the connection between ions and conductivity

In an aqueous solution, the conductivity depends on the concentration of ions present. The more ions available in the solution, the better the solution can conduct electricity, as these ions serve as charge carriers.

Step 4: Explain why HNO\(_3\) is a better conductor

Since \(\mathrm{HNO}_3\) is a strong acid, it completely dissociates/ionizes in water, leading to a higher concentration of ions in the solution. This results in a better conducting solution, as there are more charge carriers (ions) available. On the other hand, \(\mathrm{HNO}_2\) is a weak acid and partially dissociates/ionizes in water. This leads to a lower concentration of ions in the solution, resulting in a poorer conducting solution. In summary, a \(1.0 M\) aqueous solution of \(\mathrm{HNO}_{3}\) is a better conductor of electricity than a \(1.0 M\) solution of \(\mathrm{HNO}_{2}\) because \(\mathrm{HNO}_3\) is a strong acid that fully dissociates/ionizes in water, resulting in more ions in the solution, which are responsible for conducting electricity.