Neutralization number is measured in:

Neutralization number is defined as the amount of a strong base, typically expressed in milligrams of potassium hydroxide (KOH), required to neutralize one gram of a sample. This measurement is crucial in various chemical applications, particularly in determining the amount of acid present in a sample or evaluating the quality of a substance.

Potassium hydroxide is frequently used as a standard for this measurement because of its reliability and well-known properties as a strong base. The neutralization number reflects the quantity of base that completely reacts with the acidic components of the sample, thus providing valuable information for industries such as food science, pharmaceuticals, and chemical manufacturing.

The other options involve different substances that do not represent the standardized method for measuring neutralization number. For instance, sodium hydroxide (NaOH) and hydrochloric acid (HCl) have their own specific applications, but they are not the standard for this particular measurement. Therefore, using KOH as the baseline provides consistency and facilitates communication about neutralization characteristics across different contexts and applications.