What is the difference between a strong and weak acid and bases?
The correct answer and explanation is:
A strong acid or base completely dissociates in water, while a weak acid or base only partially dissociates.
A strong acid is an acid that dissociates entirely into its ions when dissolved in water. For example, hydrochloric acid (HCl) dissociates completely into H⁺ and Cl⁻ ions. This means that in a solution of a strong acid, the concentration of hydrogen ions (H⁺) is very high, leading to a low pH. The greater the concentration of H⁺ ions, the stronger the acid. Strong acids are capable of reacting vigorously with bases and other substances.
On the other hand, a weak acid only partially dissociates in water. An example is acetic acid (CH₃COOH), which only partially ionizes into H⁺ and acetate (CH₃COO⁻) ions in solution. As a result, the concentration of hydrogen ions is lower in a weak acid solution, leading to a higher pH compared to a strong acid of the same concentration. The degree of dissociation of weak acids can be expressed by the acid dissociation constant (Ka), where smaller values of Ka indicate weaker acids.
The same principle applies to strong bases and weak bases. A strong base, like sodium hydroxide (NaOH), dissociates completely in water to form hydroxide ions (OH⁻), increasing the pH of the solution significantly. A weak base, such as ammonia (NH₃), only partially reacts with water to form OH⁻ ions, resulting in a solution that is less basic.
The key difference between strong and weak acids or bases lies in the extent to which they dissociate in water. Strong acids and bases dissociate fully, creating solutions with high concentrations of ions, while weak acids and bases dissociate partially, leading to lower concentrations of ions. This influences their ability to conduct electricity, their reactivity, and their overall strength in chemical reactions.