HSSC II PBA CHEMISTRY
Curriculum 2006
Detailed Practical Notes
Section A – (60% Practical Marks)
1. Detection of Cations
(Dry & Wet Tests)
Apparatus: Test tubes, Bunsen burner, Nichrome wire loop, Reagents (NaOH, NH₄OH).
Procedure:
Dry Test: Heat a small amount of salt in a dry test tube or on a loop dipped in HCl, observe flame color.
Wet Test: Dissolve salt in distilled water. Add NaOH/NH₄OH drop by drop and observe precipitates. Use group reagents for confirmation.
Result:
Dry Test: Cu²⁺ – Blue-green, Na⁺ – Yellow, K⁺ – Lilac, Ba²⁺ – Apple green.
Wet Test: Fe³⁺ – Brown ppt, Zn²⁺ – White ppt soluble in excess NaOH.
2. Detection of Anions
(Wet Tests)
Apparatus: Test tubes, dropper, Reagents (HCl, H₂SO₄, AgNO₃, BaCl₂).
Procedure:
Add dilute acids to salt solution and observe gas or precipitate.
Use confirmatory tests like AgNO₃ for Cl⁻, BaCl₂ for SO₄²⁻, and FeSO₄/H₂SO₄ for NO₃⁻.
Result:
CO₃²⁻: Effervescence (CO₂ gas),
SO₄²⁻: White ppt with BaCl₂,
Cl⁻: White ppt with AgNO₃,
NO₃⁻: Brown ring with FeSO₄.
3. Identification of Aldehyde and Ketone
Apparatus: Test tubes, Tollens’ reagent, Fehling’s solutions A & B, 2,4-DNP reagent.
Procedure:
Add reagents to test samples separately and observe reactions.
Tollens’ for silver mirror, Fehling’s for red ppt, 2,4-DNP for precipitate.
Result:
Aldehyde: Tollens’ – Silver mirror; Fehling’s – Red ppt; 2,4-DNP – Orange ppt.
Ketone: No reaction in Tollens’ and Fehling’s; positive 2,4-DNP test.
Section B – (40% Practical Marks)
4. Preparation of Nickel Dimethyl Glyoxime Complex
Apparatus: Beaker, glass rod, Reagents (Dimethyl glyoxime, Nickel salt).
Procedure:
Add dimethyl glyoxime solution to nickel salt.
Stir to allow red precipitate formation.
Result:
Red precipitate confirms presence of Ni²⁺.
5. Preparation of Iodoform
Apparatus: Test tube, ethanol/acetone, iodine, NaOH.
Procedure:
Mix iodine and NaOH with ethanol or acetone.
Warm the mixture gently.
Result:
Yellow precipitate of iodoform with antiseptic smell.
6. Identification of Carboxylic Acid Group
Apparatus: Test tube, dropper, sodium bicarbonate (NaHCO₃).
Procedure:
Add NaHCO₃ solution to the sample.
Result:
Effervescence due to CO₂ gas confirms the –COOH group.
7. Preparation of Glucosazone
Apparatus: Beaker, heat source, phenylhydrazine, glucose, glacial acetic acid.
Procedure:
Mix glucose with phenylhydrazine and acetic acid.
Heat gently.
Result:
Yellow crystals of glucosazone indicate presence of glucose.
8. Identification of Phenol Group
Apparatus: Test tube, dropper, FeCl₃ solution.
Procedure:
Add FeCl₃ to phenol solution.
Result:
Violet/purple coloration confirms phenol.
Best Wishes For Your Paper
0 Comments