Which of the following is the outcome of a neutralization reaction?

A salt

The correct answer is option 2. A salt.

A neutralization reaction is a chemical reaction between an acid and a base, resulting in the formation of a salt and water. The reaction can be represented in a general form as follows:

\[ \text{acid} + \text{base} \rightarrow \text{salt} + \text{water} \]

Here's an explanation of the key components of the neutralization reaction:

1. Acid:  An acid is a substance that donates protons (H⁺ ions) when dissolved in water. Examples include hydrochloric acid (HCl) and sulfuric acid (H₂SO₄).

2. Base: A base is a substance that accepts protons (H⁺ ions) when dissolved in water. Examples include sodium hydroxide (NaOH) and potassium hydroxide (KOH).

3. Salt: In the context of a neutralization reaction, a salt is formed by the combination of the positively charged hydrogen ions from the acid and the negatively charged hydroxide ions from the base. The specific salt formed depends on the specific acid and base used in the reaction. For example: If hydrochloric acid reacts with sodium hydroxide, the salt formed is sodium chloride (NaCl).

4. Water: Water is always a product of neutralization reactions. It is formed by the combination of the hydrogen ion (H⁺) from the acid and the hydroxide ion (OH⁻) from the base.

The overall result is the neutralization of the acidic and basic properties, leading to the formation of a salt and water. This reaction is fundamental in various chemical and biological processes and is commonly encountered in everyday life, such as in the preparation of common household items like soaps and detergents.