Calculate the percent ionization of a formic acid solution having the given concentration. c. 0.100 M

Verified step by step guidance

1. Identify the chemical formula for formic acid, which is \( \text{HCOOH} \).
2. Write the ionization equation for formic acid: \( \text{HCOOH} \rightleftharpoons \text{H}^+ + \text{HCOO}^- \).
3. Use the expression for the acid dissociation constant \( K_a \) for formic acid: \( K_a = \frac{[\text{H}^+][\text{HCOO}^-]}{[\text{HCOOH}]} \).
4. Assume initial concentration of formic acid is \( 0.100 \text{ M} \) and let \( x \) be the concentration of \( \text{H}^+ \) ions at equilibrium. Set up the expression: \( K_a = \frac{x^2}{0.100 - x} \).
5. Calculate the percent ionization using the formula: \( \text{Percent Ionization} = \left( \frac{x}{0.100} \right) \times 100 \% \).

Key Concepts

Ionization of Weak Acids

Weak acids, like formic acid, do not completely dissociate in solution. Instead, they establish an equilibrium between the undissociated acid and its ions. The degree of ionization is crucial for understanding the acid's strength and its behavior in solution.

Equilibrium Constant (Ka)

The acid dissociation constant (Ka) quantifies the strength of a weak acid by measuring the extent of ionization at equilibrium. For formic acid, the Ka value helps determine how much of the acid will ionize in a given concentration, which is essential for calculating percent ionization.

Percent Ionization Calculation

Percent ionization is calculated by taking the ratio of the concentration of ionized acid to the initial concentration of the acid, multiplied by 100. This metric provides insight into the strength of the acid and its effectiveness in solution, particularly in dilute concentrations.