ASSIGNMENT: WRITE DOWN THE CLASSICAL METHODS WHICH GIVE US QUALITATIVE AND QUANTITATIVE INFORMATION.

1. ADVANCE ANALYTICAL TECHNIQUES IN
ENVIRONMENT
ASSIGNMENT: WRITE DOWN THE CLASSICAL METHODS
WHICH GIVE US QUALITATIVE AND QUANTITATIVE
INFORMATION.
Submitted to: Dr. Nadia Jamil
Submitted by: Sadia Rahat
MS 2nd Semester
Dated:12th
April, 2015

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Qualitative test methods
Qualitative test methods show whether a particular substance is present or not. It does not give
an indication of how much is present.
Examples
1. ph indicator to see if an acid is present.
2. For metal ions, flame test and precipitate tests.
3. For non-metal ions, halide ion test and ammonium ion tests.
4. Identification of chemical salt through its particular color and shape of crystals.
5. Identification of chemical through its particular smell.
6. Boiling point is the best qualitative indication as every single chemical has its own unique
boiling point.
7. Solubility in water is also a good qualitative test method as almost all nitrates are soluble,
all chlorides, bromides, and iodides are soluble except those of silver, mercury (i), and
lead(ii) while all hydroxides and sulfides are insoluble except those of the alkali metals, the
alkaline earth metals, and ammonium.
8. Reaction with hydrochloric acid and precipitate will form with any cation that forms an
insoluble chloride such as pbcl2.
9. Reaction with sulfuric acid and precipitate will form with any cation that forms an insoluble
sulfate such as baso4.
10. Reaction with silver nitrate and precipitate will form with certain cations that form insoluble
silver compounds such as silver chloride.
Quantitative analysis
Test to identify the exact amount or concentration of an analyte that is present in a particular
sample.
Examples
1. Acid-base titration to determine exactly how much acid is present.

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2. Gravimetric analysis uses an excess of added reagent reacts with the analyte to form a
precipitate. The precipitate is filtered, dried, and weighed. Its mass is used to calculate the
concentration of the analyte in the given sample.
3. Volumetric or titrimetric analysis uses the reagent added gradually to the analyte from a
burette. The volume of added reagent corresponding to the indicator color change is the
end point of the titration which is use to calculate the amount or concentration of the
analyte in the given sample.
4. Thermo-gravimetry: the loss in weight of a substance as it decomposes upon heating is
proportional to the amount of substance initially present.
5. Conductimetry: the number of charged chemical components in a solution determines the
resistance or conductance of a solution to the passage of electrical current.
6. Potentiometry: many chemical reactions produce electric energy, a battery for example.
The amount of chemical to produce a measured potential is calculated.