Find the pH of each mixture of acids. a. 0.115 M in HBr and 0.125 M in HCHO₂

Key Concepts

Strong vs. Weak Acids

Strong acids, like HBr, completely dissociate in solution, releasing all their hydrogen ions (H+). In contrast, weak acids, such as formic acid (HCHO2), only partially dissociate, establishing an equilibrium between the undissociated acid and its ions. Understanding the difference between these types of acids is crucial for calculating the pH of mixtures.

pH Calculation

pH is a measure of the hydrogen ion concentration in a solution, calculated using the formula pH = -log[H+]. For strong acids, the pH can be directly derived from their molarity, while for weak acids, the pH requires the use of the acid dissociation constant (Ka) to determine the concentration of H+ ions at equilibrium.

Acid-Base Mixtures

When mixing strong and weak acids, the strong acid will dominate the pH due to its complete dissociation. However, the presence of the weak acid can affect the overall pH depending on its concentration and dissociation. Analyzing the contributions of both acids is essential for accurately determining the final pH of the mixture.