Definition of Qualitative Analysis in Chemistry

It provides nonnumerical information about a specimen

Flame experiment holding potassium compound on platinum wire in Bunsen Burner flame, turning flame purple
The flame test is a technique used to identify ions using qualitative analysis. Dorling Kindersley, Getty Images

In chemistry, qualitative analysis is the determination of the chemical composition of a sample. It encompasses a set of analytical chemistry techniques that provide nonnumerical information about a specimen.

Qualitative analysis can tell you whether an atom, ion, functional group, or compound is present or absent in a sample, but it doesn't provide information about its quantity. Quantification of a sample, in contrast, is called quantitative analysis.

Techniques and Tests

Qualitative analysis involves chemical tests, such as the Kastle-Meyer test for blood or the iodine test for starch. Another common qualitative test, used in inorganic chemical analysis, is the flame test.

Qualitative analysis typically measures changes in color, melting point, odor, reactivity, radioactivity, boiling point, bubble production, and precipitation. Methods include distillation, extraction, precipitation, chromatography, and spectroscopy.

Branches of Qualitative Analysis

The two main branches of qualitative analysis are organic qualitative analysis (such as the iodine test) and inorganic qualitative analysis (such as the flame test).

Inorganic analysis looks at the elemental and ionic composition of a sample, usually by examination of ions in aqueous solution. Organic analysis tends to look at types of molecules, functional groups, and chemical bonds.

Example

She used qualitative analysis to find that the solution contained Cu2+ and Clions.

Format
mla apa chicago
Your Citation
Helmenstine, Anne Marie, Ph.D. "Definition of Qualitative Analysis in Chemistry." ThoughtCo, Aug. 25, 2020, thoughtco.com/definition-of-qualitative-analysis-604626. Helmenstine, Anne Marie, Ph.D. (2020, August 25). Definition of Qualitative Analysis in Chemistry. Retrieved from https://www.thoughtco.com/definition-of-qualitative-analysis-604626 Helmenstine, Anne Marie, Ph.D. "Definition of Qualitative Analysis in Chemistry." ThoughtCo. https://www.thoughtco.com/definition-of-qualitative-analysis-604626 (accessed March 28, 2024).