Problem #29 Analytical Chemistry [Solved]

Question: There are two categories in Analytical Chemistry; what are they? Explain, and for each category give at least three analytical techniques used.

Analytical chemistry has two branches: Qualitative analysis and Quantitative analysis

(i) Qualitative analysis: is about the determination of the nature or the identity of an unknown component sample, or the nature or the identities of the unknown components of a mixture sample. Qualitative analysis is not about the determination of the quantities, it is about the determination of the quality (nature, identity) of the matter.

A qualitative analysis allows you to say: the sample is an acid or a base; the sample contains Cu²⁺, Na⁺, Cl^- ions; the sample is an alcohol, a carboxylic acid, an ester, etc....

Examples:

- Testing if a solution is acidic or basic by Litmus paper.

- Testing the presence of chemical species by a specific agent, such as testing the presence of Cl^- ions in an aqueous solution by precipitation with AgNO₃(aq) solution.

- Determination of the nature of an organic compound by IR Spectroscopy.

- Determination of the presence of a given metal by flame test.

(ii) Quantitative analysis: involves measuring the proportions or the quantities of known components present in a mixture. Different chemical techniques of quantitative analysis are used: volumetric, gravimetric, spectroscopy, spectrometry, instrumental, etc..

Examples:

- Determination of the concentration of an acid or base by titration: volumetric titration.

- Determination of the amount of Cu⁺⁺ ion present in an aqueous solution by UV-Visible Spectrophotometry.

- Determination of the pH of an aqueous solution by a pHmeter.

There are many chemical and instrumental analysis methods in Analytical chemistry.