Question

a. Write the balanced equations that describe the two-step ionization of sulfuric acid in a dilute aqueous solution. b. How do the degrees of ionization in the two steps compare?

Short answer

The first ionization step of \( H_2SO_4 \) is nearly complete, while the second is only partial. Hence, the degree of ionization is higher in the first step.

Step-by-step solution

Write the formula for sulfuric acid

Sulfuric acid is represented by the chemical formula \( H_2SO_4 \).

Write the first ionization step

The first ionization of sulfuric acid in water involves losing one hydrogen ion (proton): \[ H_2SO_4 (aq) \rightarrow H^+ (aq) + HSO_4^- (aq) \]

Write the second ionization step

The second ionization step involves the dissociation of the hydrogen sulfate ion: \[ HSO_4^- (aq) \rightarrow H^+ (aq) + SO_4^{2-} (aq) \]

Compare the degrees of ionization

The first ionization step of sulfuric acid is almost complete in a dilute aqueous solution, making \( H_2SO_4 \) a strong acid. The second ionization step is only partially complete, as \( HSO_4^- \) is a weak acid compared to the strong acid behavior of \( H_2SO_4 \). Hence, the degree of ionization is higher in the first step compared to the second.

Key concepts

Chemical Equations

Chemical equations represent reactions in a concise way. They show reactants (substances at the start) and products (substances formed). For sulfuric acid, understanding these representations allows us to see how it breaks down in steps.

In a chemical equation, symbols and formulas denote the elements and compounds involved. For example, sulfuric acid is written as \(H_2SO_4\), which tells us it has 2 hydrogen (\(2H\text{^+}\text{ ions}\text{ }\text{), }\) one sulfur (\text{S}\text{}), and 4 oxygen (\text{4O}) atoms.

Equations also balance the number of atoms for each element on both sides of the reaction arrow. This conserves mass and adheres to the Law of Conservation of Mass. We use coefficients (numbers in front of formulas) to balance these equations. For instance, \( H_2SO_4 (aq) \rightarrow H^+ (aq) + HSO_4^- (aq) \) shows one sulfuric acid molecule yielding one hydrogen ion and one hydrogen sulfate ion.

Understanding chemical equations helps in visualizing and predicting chemical behavior, which is fundamental in chemistry.

Ionization Steps

Ionization describes how molecules separate into ions, typically in water. Sulfuric acid ionizes in steps, shedding hydrogen ions. These steps are essential to understand its reactivity and strength as an acid.

**First Step:** The initial ionization step of sulfuric acid involves losing the first proton:
\[ H_2SO_4 (aq) \rightarrow H^+ (aq) + HSO_4^- (aq) \]
This reaction occurs almost completely, indicating sulfuric acid is a strong acid.

**Second Step:** The second ionization step involves the dissociation of the hydrogen sulfate ion:
\[ HSO_4^- (aq) \rightarrow H^+ (aq) + SO_4^{2-} (aq) \]
This reaction is only partial because hydrogen sulfate (HSO\textsubscript{4}\textsuperscript{-}) is a weaker acid.

Each step is essential to understanding sulfuric acid's behavior in solution. The degree of ionization differs significantly between steps, with the first one being nearly complete and the second one less complete.

Sulfuric Acid

Sulfuric acid, with the chemical formula \(H_2SO_4\), is a strong acid widely used in industry. Its ability to ionize in water makes it a key player in various chemical processes.

Sulfuric acid has two places where it can lose hydrogen ions (ionize).

• **First Ionization:** In water, it first loses one hydrogen ion almost completely: \[ H_2SO_4 (aq) \rightarrow H^+ (aq) + HSO_4^- (aq) \]
• **Second Ionization:** The second ionization releases another hydrogen ion: \[ HSO_4^- (aq) \rightarrow H^+ (aq) + SO_4^{2-} (aq) \]

Because sulfuric acid is a strong acid, its first ionization step is nearly complete in dilute solutions. Its second ionization step, however, is only partial because the hydrogen sulfate ion is a weaker acid.

Given its strong acidic properties, sulfuric acid is used in fertilizer production, chemical synthesis, and wastewater treatment. Understanding its ionization behavior is crucial for its safe and efficient use in these applications.