Which of the following is not an
example of qualitative chemical analysis? (A) Determining the concentration
of a compound in solution. (B) Identifying the cationic groups
in a compound. (C) Identifying the anionic groups
in a compound. (D) Identifying the functional
group in a molecule. Or (E) determining the elemental
composition of a molecule.
There are two ways to analyze a
chemical sample: by qualitative analysis or by quantitative analysis. Qualitative analysis is the
identification of substances in a sample, in other words identifying what
constituents a sample is composed of, be it elements, ions, or molecules or a
mixture of these, whereas quantitative analysis is the determination of the quantity
or amount or abundance of a substance, be it elements, ions, molecules in a
sample. So qualitative analysis involves
finding out the identity of an analyte, while quantitative analysis involves finding
out the quantity of the analyte.
The question asks, which of the
following is not an example of qualitative chemical analysis? In other words, they are asking us,
which answer is an example of quantitative analysis where we measure the quantity of
an analyte? There are various ways to measure
the amount of an analyte in a sample. We can measure its mass, or we can
determine its concentration, or we can express its amount in terms of moles or as a
percentage in relative abundance.
So determining the concentration of
a compound in solution is an example of quantitative analysis. Identifying cationic groups is a
qualitative analysis. Identifying anionic groups is also
a qualitative process. Identifying which functional groups
are present is not a measurement of the amount of analyte, and so we can rule this
answer option out too. And lastly, determining the
elemental composition is all about determining which elements are present and not
the amount of each element.
Finally, which of the following is
not an example of qualitative chemical analysis? The answer is (A) determining the
concentration of a compound in solution.