Weak acids are substances that partially dissociate in water, meaning they do not completely break apart into ions. This results in a lower concentration of hydrogen ions compared to strong acids. Common examples of weak acids include acetic acid, found in vinegar, and citric acid, present in citrus fruits. Due to their partial ionization, weak acids have a less intense sour taste and are often used in food preservation and flavoring. They also play important roles in biological systems, such as maintaining the pH balance in cells and participating in various metabolic processes.