Classroom

Chemistry Past Questions

Study and practice Chemistry past questions with answers and detailed explanations. Then test your knowledge using our interactive CBT practice platform and prepare confidently for your upcoming examinations.

2,505 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

Select subject

Download PHP app Ask a Question Check Syllabus Past Question Videos Topic Video Lessons

Take a test

Custom CBT

Create and set up a CBT environment with your preferred subjects.

JAMB CBT Simulator

Practice JAMB CBT with real UTME past questions in CBT format.

WAEC CBT Practice 2026 Simulator

CB-WASSCE styled past question practice.

NECO CBT Practice 2026 Simulator

SSCE & GCE styled past question practice.

Past Questions

2,505 questions

Question 1 of 20 2,505 total questions

Question 931

jamb 1991

Copper (II) tetraoxosulphate (IV) is widely used as a?

Afertilizer

Bfungicide

Cdisinfectant

Dpurifier

View Explanation & Discuss

Question 932

jamb 1991

Which of the following metals can be prepared in samples by the thermal decomposition of their trioxonitrate (V) salts?

ACopper and mercury

BSilver and copper

CMercury and silver

DMagnesium and mercury

View Explanation & Discuss

Question 933

jamb 1991

Which of the following, in clear solution, forms a white precipitate when carbon (IV) oxide is bubbled into it for a short time?

AKOH

BNaOH

CCa(OH)₂

DAI(OH)₃

View Explanation & Discuss

Question 934

jamb 1991

Addition of aqueous ammonia to a solution of Zn⁺⁺ gives a white precipitate which dissolves in an excess of ammonia because?

Azinc is amphoteric

Bzinc hydroxide is readily soluble

Czinc forms a complex which is readily soluble in excess ammonia

Dammonia solution is a strong base

View Explanation & Discuss

Question 935

jamb 1991

Oxygen gas can be prepared by heating?

Aammonium trioxonitrate (V)

Bammonium trioxonitrate (III)

Cpotassium trioxonitrate (V)

Dmanganese (IV) oxide

View Explanation & Discuss

Question 936

jamb 1991

Which of the following salts can be melted without decomposition?

ANa₂CO₃

BCaCO₃

CMgCO₃

DZnCO₃

View Explanation & Discuss

Question 937

jamb 1991

Which of the following gases will rekindle a brightly glowing splint?

ANO₂

BNO

CN₂O

DCI₂

View Explanation & Discuss

Question 938

jamb 1991

Which of the following equilibria is unaffected by a pressure change?

A2NaCI(s) ↔ 2Na _(I) + CI_2(g)

BH _2(g) + I_2(g) ↔ 2HI_(g)

C2O_3(g) ↔ 3O_2(g)

D2NO_2(g) ↔ N₂O_4(g)

View Explanation & Discuss

Question 939

jamb 1991

NO(g) + CO(g) ↔ (1)/(2)N2(g) + CO2(g) ∆H = 89.3 kj.
What conditions would favour maximum conversion of nitrogen (II) oxide and carbon (II) oxide in the reaction above?

ALow temperature and high pressure

BHigh temperature and low pressure

CHigh temperature and high pressure

DLow temperature and low pressure

View Explanation & Discuss

Question 940

jamb 1991

1.1 g of CaCI2 dissolved in 50 cm3 of water caused a rise in temperature of 3.4°C. The heat of reaction, ∆H for CaCI2 in kj per mole is?

(Ca = 40, CI = 35.5, specific heat of water is 4.18 jk-1)

A-71.1

B-4.18

C+71.1

D+111.0

View Explanation & Discuss

Question 941

jamb 1991

Magnesium (IV) oxide is known to hasten the decomposition of hydrogen peroxide. Its main action is to?

Aincrease the surface area of the reactants

Bincrease the concntration of the reactants

Clower the activation energy for the reaction

Dlower the heat of reaction, ∆H, for the reaction

View Explanation & Discuss

Question 942

jamb 1991

2H2S(g) + SO2(g) → 3S(s) + 2H2O(I). The above reaction is?

Aa redox reaction H₂S is the oxidant and SO₂ is the reductant

Ba redox reaction in which SO₂ is the oxidant and H₂S is the reductant

Cnot a redox reaction because there is no oxidant in reaction equation

Dnot a redox because there is no reductant in the reaction equation

View Explanation & Discuss

Question 943

jamb 1991

MnO^-₄ + 8H⁺ + ne → Mn⁺⁺ + 4H₂O. Which is the value of n in the reaction above?

View Explanation & Discuss

Question 944

jamb 1991

Which of the following equimolar solutions, Na₂CO₃ Na₂ SO
₄CI FeCI₃ CH₃COONa,
have pH greater than 7?

AFeCI ₃ and NH ₄CI

BNa₂CO₃, CH₃COONa and Na,Na₂SO₄

CNa₂CO₃ and CH₃COONa

DFeCI₃, CH₃COONa and NH₄CI

View Explanation & Discuss

Question 945

jamb 1991

If a current of 1.5 A is passed for 4.00 hours through a molten tin salt and 13.3g of tin is deposited, what is the oxidation state of the metal in the salt?

(Sn = 118.7, F = 96500 C mol^-1)

View Explanation & Discuss

Question 946

jamb 1991

What volume of CO\(_2\) at s.t.p would be obtained by reacting 10cm\(^3\) of 0.1M solution of anhydrous sodium trioxocarbonate (IV) with excess acid?

(G.M.V at s.t.p = 22.4 dm\(^3\))

A2.240 cm ³

B22.40 cm ³

C224.0 cm ³

D2240 cm ³

View Explanation & Discuss

Question 947

jamb 1991

How many structural isomers can be written for the alkyl bromide, C₄H₉Br?

View Explanation & Discuss

Question 948

jamb 1991

50 cm\(^3\) of sulphur (IV) oxide, 800cm\(^3\) of ammonia, 450 cm\(^3\) of hydrogen chloride, 1.0 cm\(^3\)of Carbon(IV) oxide will respectively saturate 1.0 cm\(^3\) of water at 15°C. Which of the following is suitable for demonstrating the fountain experiment?

ASulphur (IV) oxide and hydrogen chloride

BCarbon (IV) oxide and ammonia

CAmmonia and hydrogen chloride

DCarbon (IV) oxide and surphur (IV) oxide

View Explanation & Discuss

Question 949

jamb 1991

A property of a colloidal dispersion which a solution does not have is?

Athe Tyndall effect

Bhomogeneity

Cosmotic pressure

Dsurface polarity

View Explanation & Discuss

Question 950

jamb 1991

A sample of temporary hard water can be prepared in the laboratory by?

Adisolving calcium chloride in distilled water

Bsaturating lime water with carbon (IV) oxide

Csaturating distilled water with calcium hydroxide

Ddissolving sodium hydrogen trioxocarbonate (IV) in some distilled water

View Explanation & Discuss

Question Navigator

Current

Chemistry Past Questions

Take a test

Custom CBT

JAMB CBT Simulator

WAEC CBT Practice 2026 Simulator

NECO CBT Practice 2026 Simulator

Past Questions

Question Navigator

MathsFaculty