A molecule that binds up excess hydrogen ions in a solution is a(n)
A.acid
B.solvent
C.isotope
D.base
The correct answer and explanation is:
Correct Answer: D. base
A base is a molecule or substance that reduces the hydrogen ion (H⁺) concentration in a solution. It does this by either accepting hydrogen ions or releasing hydroxide ions (OH⁻), which then combine with the hydrogen ions to form water. This process decreases the overall acidity of the solution, making it more basic or alkaline.
Acids and bases are fundamental concepts in chemistry, particularly in the study of pH. The pH scale ranges from 0 to 14. Solutions with a pH below 7 are considered acidic, while those above 7 are considered basic. A neutral solution, such as pure water, has a pH of 7. Bases help maintain pH balance by neutralizing excess hydrogen ions. This neutralization is especially important in biological systems, where stable pH levels are crucial for enzyme activity and other cellular functions.
For example, in human blood, the pH must stay within a very narrow range around 7.35 to 7.45. If the blood becomes too acidic, meaning too many hydrogen ions are present, buffer systems involving bases such as bicarbonate (HCO₃⁻) help to restore balance by binding the excess hydrogen ions. The reaction might look like this:
H⁺ + HCO₃⁻ → H₂CO₃ → CO₂ + H₂O
This chemical pathway helps the body remove excess hydrogen ions through respiration and urine. Without such buffering systems involving bases, the body could experience harmful conditions like acidosis or alkalosis.
In summary, a base is the correct answer because it helps regulate the hydrogen ion concentration in a solution, thereby reducing acidity and contributing to the maintenance of chemical balance in various systems.