The substance that produces hydroxide ions in water. A. Acid B. Base C. Elements
The Correct Answer and Explanation is:
The correct answer is B. Base.
A base is a substance that produces hydroxide ions (OH⁻) when dissolved in water. This is a fundamental characteristic of bases in aqueous solutions, and it is part of the Arrhenius definition of acids and bases. According to this definition, bases increase the concentration of hydroxide ions (OH⁻) in water, which makes the solution more alkaline (basic).
Explanation:
- Bases: A base, when dissolved in water, dissociates to release hydroxide ions. For example, sodium hydroxide (NaOH) dissolves in water to produce sodium ions (Na⁺) and hydroxide ions (OH⁻). The hydroxide ions increase the pH of the solution, making it basic. Example:
NaOH→Na++OH−\text{NaOH} \rightarrow \text{Na}^+ + \text{OH}^-NaOH→Na++OH− - Acids: In contrast, acids are substances that produce hydrogen ions (H⁺) when dissolved in water. These hydrogen ions lower the pH of the solution, making it acidic. For example, hydrochloric acid (HCl) dissociates in water to produce hydrogen ions (H⁺). Example:
HCl→H++Cl−\text{HCl} \rightarrow \text{H}^+ + \text{Cl}^-HCl→H++Cl− - Elements: Elements are pure substances made up of only one type of atom. While some elements can form acids or bases when they react with water (like sodium forming NaOH or chlorine forming HCl), elements themselves do not directly produce hydroxide ions.
In summary, bases are characterized by the ability to release hydroxide ions in water, increasing the solution’s pH and making it more alkaline. Acids, on the other hand, release hydrogen ions, making the solution more acidic.
