Classify each acid as strong or weak. If the acid is weak, write an expression for the acid ionization constant (K_a). d. H₂SO₃

Verified step by step guidance

1. Identify the acid: The given acid is sulfurous acid, \( \text{H}_2\text{SO}_3 \).
2. Determine if the acid is strong or weak: Sulfurous acid (\( \text{H}_2\text{SO}_3 \)) is a weak acid.
3. Understand what a weak acid means: A weak acid partially ionizes in solution, meaning it does not completely dissociate into its ions.
4. Write the ionization reaction: \( \text{H}_2\text{SO}_3 (aq) \rightleftharpoons \text{H}^+ (aq) + \text{HSO}_3^- (aq) \).
5. Write the expression for the acid ionization constant (\( K_a \)): \( K_a = \frac{[\text{H}^+][\text{HSO}_3^-]}{[\text{H}_2\text{SO}_3]} \).

Key Concepts

Strong vs. Weak Acids

Strong acids completely dissociate in water, releasing all their protons (H+), while weak acids only partially dissociate. This distinction is crucial for understanding acid behavior in solution and predicting the extent of ionization.

Acid Ionization Constant (Ka)

The acid ionization constant (Ka) quantifies the strength of a weak acid by measuring the equilibrium concentration of its ions in solution. It is defined by the expression Ka = [H+][A-]/[HA], where [H+] is the concentration of hydrogen ions, [A-] is the concentration of the conjugate base, and [HA] is the concentration of the undissociated acid.

H2SO3 as a Weak Acid

H2SO3, or sulfurous acid, is classified as a weak acid because it does not fully dissociate in solution. Its ionization can be represented by the equation H2SO3 ⇌ H+ + HSO3-, and the corresponding Ka expression can be written to reflect this equilibrium.