To answer the question of how to best define a base, we need to understand the properties and behavior of bases in solutions.
1. Option A: Stays in a solution whenever it contains hydrogen ions.
- This statement is incorrect because bases do not simply stay in the solution; they have a specific role in relation to hydrogen ions.
2. Option B: Adds hydrogen ions to a solution.
- This statement is also incorrect. Adding hydrogen ions to a solution is the behavior of an acid, not a base. Acids donate hydrogen ions (H⁺) into the solution.
3. Option C: Removes hydrogen ions from a solution.
- This is the correct definition. Bases are substances that reduce the concentration of hydrogen ions (H⁺) in a solution. They achieve this by either accepting H⁺ ions or producing hydroxide ions (OH⁻) that combine with H⁺ to form water.
4. Option D: Both captures and releases hydrogen ions in a solution.
- This statement is partially true for buffers, substances that can both capture and release hydrogen ions to maintain a stable pH, but it is not a specific characteristic of bases alone.
Summarizing the analysis, the best definition of a base is "a substance that removes hydrogen (H⁺) ions from a solution." Therefore, the correct answer is:
C. removes hydrogen [tex]\(\left( H ^{+}\right)\)[/tex] ions from a solution.
