WAEC/GCE 2026/2027 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/GCE 2026/2027 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_bCa​Va​=Cb​Vb​

CaVa=CbVbC_a V_a = C_b V_bCa​Va​=Cb​Vb​

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

(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}na​Ca​Va​​=nb​Cb​Vb​​

CaVana=CbVbnb\frac{C_a V_a}{n_a} = \frac{C_b V_b}{n_b}na​Ca​Va​​=nb​Cb​Vb​​

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/GCE 2026/2027 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)

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SUMMARY TABLE – QUESTION BREAKDOWN

|Question|Topic|Marks|

|Q1|Volumetric (H₂SO₄ vs NaOH)|25|

|Q2|Qualitative (PbCO₃ + starch)|25|