What neutralizes an acid in a chemical reaction?

In a chemical reaction, a base or alkali neutralizes an acid. This process involves the reaction of an acid, which contains hydrogen ions (H+), with a base, which provides hydroxide ions (OH-). When these two components combine, they form water (H2O) and a salt, leading to a decrease in the acidity of the solution.

The concept of neutralization is crucial in many chemical applications, including titrations and understanding pH levels. Bases can come in various forms, such as metal oxides, metal hydroxides, and carbonates, all of which can react with acids to mitigate acidity, thus achieving a pH level closer to neutral (pH 7).

The other choices do not have the same neutralizing effect on acids. Gases may or may not react with acids, but they do not specifically neutralize them. Salts are the products of a neutralization reaction but do not act to neutralize acids on their own when introduced. Metals can react with acids, often producing hydrogen gas and a salt, but this is not a neutralization process; instead, it leads to the release of gas and the formation of a dissolved ionic compound. Therefore, a base or alkali is the