What is a substance that can neutralize an acid called?

A substance that can neutralize an acid is referred to as a base. Bases are defined as substances that can donate hydroxide ions (OH-) or accept protons (H+). When a base reacts with an acid, a neutralization reaction occurs, resulting in the formation of water and a salt. This reaction effectively reduces the acidity of the solution, thereby neutralizing the acid.

In contrast, salts are the products formed from the neutralization of an acid and a base but are not themselves neutralizing agents. Buffers are specialized solutions that resist changes in pH upon the addition of small amounts of an acid or a base, but they do not inherently neutralize acids like a base does. Acids, on the other hand, are substances that can donate protons or increase the concentration of hydrogen ions in a solution, which is the opposite of what is needed for neutralization. Thus, the identification of a base as the correct answer is grounded in its fundamental ability to counteract the properties of an acid.