WAEC 2026 Specimen List and Chemistry Practical Questions and Answers
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
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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
2026 WAEC CHEMISTRY PRACTICAL QUESTIONS AND ANSWERS (ALT A/ALT B)
Candidates supplied with:
Solution Aₙ = H₂SO₄ (0.0500 mol/dm³ assumed)
Solution Bₙ = NaOH (0.100 mol/dm³ assumed)
Solid Cₙ = 1:1 mixture of PbCO₃ + starch
Indicators: Methyl orange, phenolphthalein
—
QUESTION 1 (Volumetric Analysis) – 25 marks
(a) Calculate conc of Aₙ in mol/dm³ if 4.90 g/dm³ (Molar mass H₂SO₄ = 98 g/mol).
Ans: 4.90/98 = 0.0500 mol/dm³ (2 marks)
(b) Balanced equation for Aₙ + Bₙ.
Ans: H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O (2 marks)
(c) Titrate Aₙ vs Bₙ using methyl orange.
Pipette 25.0 cm³ Aₙ + 2-3 drops methyl orange.
Titrate with Bₙ until colour changes from red to yellow.
Tabulate readings:
|Burette reading|Rough|1st|2nd|3rd|
|Final (cm³)|25.00|24.80|24.90|24.80|
|Initial (cm³)|0.00|0.00|0.00|0.00|
|Titre (cm³)|25.00|24.80|24.90|24.80|
Average titre = (24.80+24.90+24.80)/3 = 24.83 cm³ (6 marks)
(d) Calculate conc of Bₙ in mol/dm³.
Using CaVa/CbVb = na/nb
(0.0500 × 25.0)/Cb × 24.83 = 1/2
Cb = (0.0500 × 25.0 × 2)/24.83 = 0.1007 mol/dm³ (5 marks)
(e) Moles of H₂SO₄ in 25.0 cm³ Aₙ = 0.0500 × (25/1000) = 0.00125 moles (3 marks)
(f) Mass of NaOH in 1 dm³ Bₙ = 0.1007 × 40 = 4.028 g.
Given = 4.00 g.
% error = (0.028/4.00) × 100 = 0.7% (4 marks)
(g) One precaution: Rinse burette with Bₙ before filling. (1 mark)
(h) Why methyl orange over phenolphthalein?
Methyl orange changes colour at pH 3.7-4.4 (acidic), suitable for strong acid vs strong base, sharper endpoint for H₂SO₄/NaOH. (2 marks)
—
QUESTION 2 (Qualitative Analysis – Solid Cₙ = PbCO₃ + starch) – 25 marks
(a) Appearance: White powder, slightly gritty. (2 marks)
(b) Solubility (water + filter):
|Observation|Inference|
|White residue, slightly cloudy filtrate|PbCO₃ insoluble, starch slightly soluble|
(2 marks)
(c) Carbonate test: Residue + dil HCl, gas to limewater.
|Observation|Inference|
|Effervescence, limewater turns milky|CO₂ gas – carbonate present|
(4 marks)
(d) Test for Pb²⁺: Dissolve Cₙ in dil HNO₃. Split into two.
|Test|Observation|Inference|
|+ dil H₂SO₄|White precipitate|PbSO₄ formed|
|+ KI solution|Yellow precipitate|PbI₂ formed|
(6 marks)
(e) Starch test: Cₙ + water, boil, cool + iodine.
|Observation|Inference|
|Deep blue/black colour|Starch confirmed|
(3 marks)
(f) Flame test: Paste Cₙ + conc HCl on wire loop, place in flame.
|Observation|Inference|
|Blue/green flame|Pb²⁺ present|
(3 marks)
(g) Confirm Pb²⁺: Solution from (d) + NH₃ dropwise then excess.
|Observation|Inference|
|White precipitate, insoluble in excess|Pb(OH)₂ – confirms Pb²⁺|
(2 marks)
(h) Conclusion:
Cations: Pb²⁺
Anions: CO₃²⁻, plus starch (non-ionic) (3 marks)
QUESTION 3 (General Practical – 5 unknowns P,Q,R,S,T) – 20 marks
(a) Sample P (white solid)
|Test|Observation|Inference|
|Heat strongly|White sublimate, gas turns splint off|NH₄⁺, thermal decomposition|
|Burning splint|Splint extinguishes|CO₂ or no O₂|
(4 marks)
(b) Sample Q (aqueous solution)
|Test|Observation|Inference|
|+ NaOH dropwise then excess|White precipitate, soluble in excess|Zn²⁺ present|
|+ NH₃ dropwise then excess|White precipitate, soluble in excess|Zn²⁺ confirmed|
(4 marks)
(c) Sample R (colourless solution)
|Test | Observation| Inference|
|+ BaCl₂ then dil HCl |White precipitate, insoluble in HCl|SO₄²⁻ present|
(3 marks)
(d) Sample S (blue salt solution)
|Test |Observation| Inference|
|+ NH₃ dropwise |Blue precipitate|Cu²⁺ present|
|+ NH₃ in excess |Deep blue solution|[Cu(NH₃)₄]²⁺ formed|
(3 marks)
(e) Sample T (Cl⁻, SO₄²⁻, NO₃⁻ mixture)
|Test |Observation |Inference|
|+ AgNO₃ + HNO₃|White precipitate, soluble in NH₃|Cl⁻ present|
|+ BaCl₂ + HCl |White precipitate, insoluble|SO₄²⁻ present|
|+ conc H₂SO₄ + Cu turnings |Brown gas (NO₂) evolved |NO₃⁻ present|
(6 marks)
—
SUMMARY TABLE – QUESTION BREAKDOWN
|Question|Topic|Marks|
|Q1|Volumetric (H₂SO₄ vs NaOH)|25|
|Q2|Qualitative (PbCO₃ + starch)|25|
