What is the definition of analytical chemistry?

Analytical chemistry is defined as a branch of chemistry that emphasizes the qualitative and quantitative analysis of substances. This includes both identifying the components of a sample (qualitative analysis) and measuring the amounts of those components (quantitative analysis).

The correct answer highlights the dual focus of analytical chemistry: it not only seeks to determine what substances are present but also how much of each substance is present. This is essential for a wide range of applications, including pharmaceuticals, environmental monitoring, and food safety, where both the identification of compounds and their concentrations are critical for safety and efficacy.

In contrast, other choices either limit the scope of analytical chemistry or misrepresent its focus. The study of chemical reactions refers more generally to the field of chemistry rather than the specific practices of analysis. Synthesizing new compounds pertains to organic or inorganic chemistry, where the emphasis is on reaction pathways rather than analysis. Focusing solely on qualitative analysis disregards the quantitative aspect, which is a fundamental part of analytical chemistry's purpose and practice.