Potassium hydroxide is a strong base. This means that
A. KOH dissociates completely to f(aq) and OH(aq) when it dissolves in water
B. aqueous solutions of KOH contain equal concentrations of Ht(aq) and OH”(aq)
C. KOH cannot be neutralized by a weak acid
D. KOH produces a gaseous product when it is neutralized
E. KOH does not dissociate at all when it is dissolved in water
The Correct Answer and Explanation is :
The correct answer is: A. KOH dissociates completely to K⁺(aq) and OH⁻(aq) when it dissolves in water.
Explanation:
Potassium hydroxide (KOH) is classified as a strong base. A strong base is a substance that completely dissociates into its constituent ions when dissolved in water. KOH is an example of this, as it breaks apart completely into potassium ions (K⁺) and hydroxide ions (OH⁻) in aqueous solution.
When KOH dissolves in water, the process of dissociation can be represented by the following equation:
[
\text{KOH} \ (s) \rightarrow \text{K}^+ \ (aq) + \text{OH}^- \ (aq)
]
This dissociation process is the key feature of strong bases. Unlike weak bases, which only partially dissociate in water, strong bases like KOH fully dissociate, leading to a higher concentration of hydroxide ions (OH⁻) in the solution. This high concentration of hydroxide ions is what makes KOH a strong base, as the presence of OH⁻ ions in solution causes the pH to be very high (typically above 12 in concentrated solutions).
Now let’s address why the other options are incorrect:
- B. Aqueous solutions of KOH contain equal concentrations of H⁺(aq) and OH⁻(aq): This is not correct. Strong bases like KOH have a high concentration of OH⁻ ions and very low concentrations of H⁺ ions, making the solution basic rather than neutral.
- C. KOH cannot be neutralized by a weak acid: This is incorrect. KOH, being a strong base, can be neutralized by weak acids like acetic acid (CH₃COOH) as well as strong acids. The reaction would produce water and a salt.
- D. KOH produces a gaseous product when it is neutralized: This is not true for KOH. When KOH reacts with an acid, it produces water and a salt, but no gaseous products.
- E. KOH does not dissociate at all when it is dissolved in water: This is false. KOH is a strong base, meaning it dissociates completely in water.
In conclusion, the key characteristic of KOH as a strong base is its complete dissociation in water, making option A the correct answer.
Let me generate a visual for better understanding.
Here’s the chemical diagram illustrating the dissociation of potassium hydroxide (KOH) in water. It shows how KOH breaks apart into K⁺ ions and OH⁻ ions in an aqueous solution. This should help you visualize the process more clearly. Let me know if you need more details!
