WAEC 2026 Specimen List and Chemistry Practical Questions and Answers
Qualitative Analysis (Salt Analysis)
- Sample A (Solid salt): Typically one unknown such as
- Copper(II) sulphate / Iron(II) sulphate / Zinc chloride / Ammonium salt
- Reagents provided:
- Dilute hydrochloric acid (HCl)
- Dilute nitric acid (HNO₃)
- Sodium hydroxide (NaOH) solution
- Aqueous ammonia (NH₃)
- Barium chloride (BaCl₂)
- Silver nitrate (AgNO₃)
- Distilled water
Volumetric Analysis
- Solution B: Standard acid (e.g., HCl or H₂SO₄)
- Solution C: Standard base (e.g., Na₂CO₃ or NaOH)
- Indicators:
- Methyl orange or Phenolphthalein
Organic Chemistry / Functional Test
- Ethanol
- Ethanoic acid
- Starch solution
- Glucose solution
General Laboratory Apparatus
- Burette, pipette, conical flask
- Test tubes, beakers
- Bunsen burner
- Retort stand
- Filter funnel
SECTION A – VOLUMETRIC ANALYSIS (20 MARKS)
You are provided with:
- Solution B (acid)
- Solution C (base)
WAEC 2026 Specimen List and Chemistry Practical Questions and Answers
1. (a) Pipette 25.0 cm³ of solution C into a conical flask.
Add 2–3 drops of indicator and titrate with solution B.
Record your readings.
(b) Tabulate your readings.
| Titration | Initial (cm³) | Final (cm³) | Titre (cm³) |
(c) Calculate the average titre.
(d) Given that:
CaVa=CbVbC_a V_a = C_b V_b
CaVa=CbVbC_a V_a = C_b V_b
Calculate the concentration of solution B.
ANSWERS (SECTION A)
- Rough titre: ~24.0–26.0 cm³
- Average titre: e.g., 25.0 cm³
- Correct substitution into formula
- Final concentration correctly computed
SECTION B – QUALITATIVE ANALYSIS (20 MARKS)
2. Perform the following tests on Sample A
(a) Add water to a portion of A. State observation.
Answer:
- Solid dissolves / partially dissolves
(b) Add NaOH solution (dropwise, then excess).
Observation:
- Blue precipitate (Cu²⁺) OR
- Green precipitate (Fe²⁺) OR
- White precipitate (Zn²⁺)
Inference:
- Presence of corresponding metal ion
(c) Add aqueous ammonia.
Observation:
- Deep blue solution → Cu²⁺
- White precipitate soluble in excess → Zn²⁺
(d) Add BaCl₂ solution after acidifying.
Observation:
- White precipitate
Inference:
- Sulphate (SO₄²⁻) present
(e) Add AgNO₃ solution.
Observation:
- White precipitate → Chloride
- Cream → Bromide
CONCLUSION:
- Likely salt = e.g., Copper(II) sulphate
SECTION C – ORGANIC / GENERAL CHEMISTRY (10 MARKS)
3. Food and Organic Tests
(a) Test for starch.
Procedure: Add iodine
Observation: Blue-black
Inference: Starch present
(b) Test for glucose.
Procedure: Add Benedict’s + heat
Observation: Brick-red precipitate
Inference: Reducing sugar present
(c) Test for ethanol.
Procedure: Add sodium metal (or oxidation test)
Observation: Effervescence
Inference: Alcohol present
4. Laboratory Techniques
(a) State two precautions during titration.
Answer:
- Read burette at eye level
- Avoid air bubbles
WAEC 2026 Specimen List and Chemistry Practical Questions and Answers
(b) State two sources of error.
Answer:
- Parallax error
- Incomplete reaction
LIKELY SPECIMENS (ADVANCED SET)
- Sample A: Mixed salt (e.g., ZnSO₄ + NH₄Cl or Fe²⁺ salt with impurity)
- Solution B: 0.050 M HCl
- Solution C: Na₂CO₃ solution (unknown concentration)
- Solution D: Organic compound (ethanol vs ethanoic acid trap)
Reagents:
NaOH, NH₃, BaCl₂, AgNO₃, dilute acids, heat source
SECTION A – VOLUMETRIC ANALYSIS (20 MARKS)
1. Titration (Precision Trap)
You are provided with:
- Solution B (acid)
- Solution C (base: Na₂CO₃)
(a) Perform titration and record readings
| Titration | Initial (cm³) | Final (cm³) | Titre (cm³) |
|---|
(b) Your titres must agree within ±0.10 cm³
(c) Calculate the average titre
(d) Given:
Na₂CO₃ + 2HCl → 2NaCl + H₂O + CO₂
Using:
CaVana=CbVbnb\frac{C_a V_a}{n_a} = \frac{C_b V_b}{n_b}
CaVana=CbVbnb\frac{C_a V_a}{n_a} = \frac{C_b V_b}{n_b}
Calculate the concentration of solution C.
TRAPS IN THIS QUESTION
- Using wrong mole ratio (1:1 instead of 1:2)
- Poor titre agreement (>0.20 cm³ loses marks)
- Wrong significant figures
EXPECTED ANSWER (GUIDE)
- Concordant titres: e.g., 24.80, 24.90, 24.85
- Average ≈ 24.85 cm³
- Correct mole ratio applied
SECTION B – QUALITATIVE ANALYSIS (20 MARKS)
2. Sample A (Mixed Salt Trap)
(a) Add water to A
Observation:
- Partially soluble
Inference:
- Mixture present
(b) Add NaOH (dropwise, then excess)
Observation:
- White precipitate forms
- Dissolves in excess
Inference:
- Zn²⁺ present
(c) Warm with NaOH
Observation:
- Pungent gas evolved turning red litmus blue
Inference:
- NH₄⁺ present
(d) Add BaCl₂ after acidifying
Observation:
- White precipitate insoluble in acid
Inference:
- SO₄²⁻ present
(e) Add AgNO₃
Observation:
- White precipitate soluble in NH₃
Inference:
- Cl⁻ present
FINAL CONCLUSION (FULL MARK ANSWER)
Sample A contains:
- Zn²⁺, NH₄⁺, SO₄²⁻, Cl⁻
→ Mixture of salts
TRAPS HERE
- Missing confirmatory test (loss of marks)
- Writing “gas” instead of identifying ammonia
- Confusing Zn²⁺ with Al³⁺
WAEC 2026 Specimen List and Chemistry Practical Questions and Answers
SECTION C – ORGANIC CHEMISTRY (10 MARKS)
3. Identify Sample D (Ethanol vs Ethanoic Acid Trap)
(a) Add Na₂CO₃
Observation:
- Effervescence (CO₂ gas)
Inference:
- Acid present → Ethanoic acid
(b) Add blue litmus
Observation:
- Turns red
(c) Warm with acidified K₂Cr₂O₇
Observation:
- Orange → Green
Inference:
- Alcohol (ethanol) present
TRAP INTERPRETATION
If both tests are positive →
Sample may be impure or mixed
EXPECTED CONCLUSION
- Either ethanoic acid OR mixture with ethanol
4. Experimental Skills (Trap-Based)
(a) State two reasons why pipette must not be blown out
Answer:
- Calibrated to deliver exact volume
- Blowing introduces error
(b) Why is methyl orange preferred to phenolphthalein here?
Answer:
- Strong acid vs weak base titration requires methyl orange
(c) State two sources of error in titration
Answer:
- Parallax error
- Air bubbles in burette
