AFOQT Practice Test

Which of the following best describes a base?

1. A substance that produces hydrogen ions

2. A compound that produces hydroxide ions

3. A neutral solution

4. A strong acid

The correct answer is: A compound that produces hydroxide ions

A base is best described as a compound that produces hydroxide ions when dissolved in water. Bases typically have the ability to accept protons (H⁺ ions) or donate electron pairs, and their presence in a solution leads to an increase in hydroxide ions (OH⁻), resulting in a higher pH value. In the context of the provided options, the first choice identifies a process related to acids, as they produce hydrogen ions (H⁺); therefore, it does not fit the definition of a base. The third option describes a neutral solution, which is neither acidic nor basic, making it inconsistent with the operational characteristics of a base. The last option related to a strong acid doesn't pertain to bases at all, as it defines the opposite characteristic, involving substances that produce hydrogen ions and lower pH levels. Hence, the definition that matches the nature of a base most accurately is that it produces hydroxide ions.