What is the difference between qualitative and quantitative analysis?

The correct choice highlights a fundamental distinction between qualitative and quantitative analysis in analytical chemistry. Qualitative analysis involves determining the presence or identity of chemical species in a sample. It answers questions like "What substances are present?" This could include identifying ions, functional groups, or molecular structures.

On the other hand, quantitative analysis focuses on measuring the amount or concentration of those identified substances. It provides answers to questions such as "How much of the substance is there?" This involves techniques and methods that can provide precise measurements of concentration, enabling scientists to quantify the extent or intensity of a particular component in the sample.

This differentiation is essential because both types of analysis serve complementary purposes in research and industrial applications. Qualitative methods might use techniques like chromatography, mass spectrometry, or spectroscopy to identify what is present, while quantitative methods involve similar techniques but are tailored to provide specific measurements of concentration or mass.