Which of the following is a characteristic of a strong acid in aqueous solution?

• A. It partially dissociates into ions.
• B. It completely dissociates into ions.
• C. It forms a weak conjugate base.
• D. It has a high $pH$ value.

Answer: (B)

Verified step by step guidance

1. Understand the concept of acid dissociation: A strong acid is one that completely dissociates into its ions in an aqueous solution. This means that when a strong acid is dissolved in water, it releases all of its hydrogen ions (H⁺) into the solution.
2. Identify the characteristics of a strong acid: A strong acid will have a low pH value, typically less than 3, because it releases a high concentration of hydrogen ions into the solution.
3. Recognize the relationship between strong acids and conjugate bases: A strong acid forms a weak conjugate base. This is because the conjugate base of a strong acid has little tendency to accept protons, as the acid has already donated its protons completely.
4. Differentiate between strong and weak acids: Unlike strong acids, weak acids only partially dissociate in solution, meaning they do not release all of their hydrogen ions. This results in a higher pH compared to strong acids.
5. Apply this understanding to the given options: The correct characteristic of a strong acid in aqueous solution is that it completely dissociates into ions, forming a weak conjugate base and resulting in a low pH value.