What does quantitative analysis determine?

Quantitative analysis focuses on measuring the amount or concentration of a specific substance within a sample. This type of analysis is critical in various applications, such as pharmaceuticals, environmental testing, and food safety, where knowing the exact concentration of an active ingredient or pollutant can impact safety and efficacy. Techniques employed in quantitative analysis include methods like titration, gravimetric analysis, and spectroscopy, all of which are designed to provide precise numerical data about the substance of interest.

The structure of a molecule pertains to qualitative analysis, which determines the identity and arrangement of atoms within a molecule but does not provide information on the quantity. Reactivity falls into the realm of chemical kinetics and thermodynamics, which study how substances interact but are not directly related to the measurement of amounts. The physical state of a sample—solid, liquid, or gas—also represents a qualitative attribute, indicating the condition of a material rather than its concentration or amount. Thus, option B is the only choice that accurately reflects the purpose of quantitative analysis.