Do bases donate or accept hydrogen ions?

In the context of acid-base chemistry, bases are defined by their ability to accept hydrogen ions (protons) from acids. This is a key characteristic of a base according to the Brønsted-Lowry definition of acids and bases. When a base comes into contact with an acid, it will accept a hydrogen ion, which can lead to the formation of a conjugate acid.

For example, when ammonia (NH₃), which is a common base, reacts with water, it accepts a hydrogen ion from water, forming ammonium (NH₄⁺) and hydroxide ions (OH⁻). This demonstrates the fundamental property of bases being proton acceptors.

On the other hand, options suggesting that bases donate hydrogen ions are reflective of the properties of acids. Similarly, the idea that bases would neither donate nor accept hydrogen ions does not align with their accepted definition in acid-base chemistry. Lastly, the concept of both donating and accepting hydrogen ions is more complicated and generally not applicable in a simple context, as it blurs the distinct roles of acids and bases.

Therefore, the correct identification of a base's role in acid-base interactions is that they accept hydrogen ions.