2. QUALITATIVE ANALYSIS
• Involves identification of specific cations or
anions present in a salt provided
The following reagents are expected to be used
i. Sodium hydroxide solution
ii. Aqueous ammonia
iii. Lead (II) nitrate solution
iv. Sulphuric (VI) acid
v. Potassium manganate (VII)
vi. Bromine water
3. Purpose of each reagent
• Sodium hydroxide and ammonia are meant to
test for cations
• Lead (II) nitrate is meant to test for; sulphate,
SO4
2−
, sulphite, SO3
2−
, chlorides, Cl−
, and
carbonates CO3
2−
• Sulphuric (VI) acid, to test for CO3
2−
and Pb2+
ions.
• Acidified potassium dichromate (VI), can be
used to test for the sulphite ions, 𝐒𝐎𝟑
𝟐−
4. Sample procedures
• To the first portion add sodium hydroxide
dropwise, till in excess
Observations Inferences
White precipitate soluble in excess Zn2+
, Pb2+
, Al3+
Observations Inferences
White precipitate insoluble in excess Ca2+, Mg2+ present
Observations Inferences
No white precipitate Na+, K+, NH4
+
, present
5. Sample procedures
• To the second portion, add a few drops of
dilute sulphuric (VI) acid.
Observations Inferences
No effervescence
No white precipitate
𝐶𝑂3
2−
absent
𝑃𝑏2+absent
Observations Inferences
Effervescence
white precipitate
𝐶𝑂3
2−
present
𝑃𝑏2+ present
6. Sample procedure
• To the third portion, add three drops of lead
(II) nitrate.(retain the mixture)
Observations Inferences
White precipitate seen 𝐒𝐎𝟒
𝟐−
, 𝐒𝐎𝟑
𝟐−
, 𝐂𝐎𝟑
𝟐−
, 𝐂𝐥−
present
Observations Inferences
No white precipitate seen 𝐒𝐎𝟒
𝟐−
, 𝐒𝐎𝟑
𝟐−
, 𝐂𝐎𝟑
𝟐−
, 𝐂𝐥− absent
7. Sample procedure
Warm the mixture obtained above.
Observations Inferences
The white precipitate dissolves 𝐂𝐥−
present
Observations Inferences
The white precipitate persists 𝐒𝐎𝟒
𝟐−
, 𝐒𝐎𝟑
𝟐−
, 𝐂𝐎𝟑
𝟐−
, present
8. Organic compounds
Add a few drops of bromine water.
Observations Inferences
Yellow bromine water
decolorises/changes to colourless
or present
Observations Inferences
Yellow bromine water not decolorised or absent
10. Organic compounds
Put universal indicator paper to the solution in
the boiling tube .
Observations Inferences
pH = 4
pH = 5
pH = 6
weakly acidic
weakly acidic
weakly acidic
Observations Inferences
pH = 1
pH = 2
pH = 3
strongly acidic
strongly acidic
strongly acidic
11. Volumetric analysis
• Answering questions in volumetric analysis
involves moving from known to unknown.
The knowns will be obtained from;
• The provided quantities up in the requirements
section
• The equation relating the reactants
• The answer to the question in the previous
section.
• From the procedure undertaken
