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.

49 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

49 questions

Question 1 of 20 49 total questions

Question 11

jamb 1989

The scale of a chemical balance is made of iron plate and coated with copper electrolytically because

Airon is less susceptible to corrosion than copper

Bcopper is twice as less susceptitible to corrosion as iron

Ccopper is less susceptible to corrosion than iron

Dcopper and iron are equally susceptible to corrosion

View Explanation & Discuss

Question 12

jamb 1989

The products of the thermal decomposition of ammonium trioxonitrate (V) are

ANO ₂ and oxygen

BNH₃ and oxygen

Cnitrogen and water

DN₂O and water

View Explanation & Discuss

Question 13

jamb 1989

Bleaching powder, CaOCI₂, H₂O, deteriorates on exposure to air because

Ait loses its water of crystallization

Batmospheric nitrogen displaces chlorine from it

Ccarbon (IV) oxide of the atmosphere displaceschlorine from it

Dbleaching agents should be stored in solution

View Explanation & Discuss

Question 14

jamb 1989

Which of the following reactions is (are) feasible?
I Br (l) + 2CI\(_2\)(aq) → 2Br(aq) + CI\(_2\)(g)
ll 2 I (aq) + Br\(_2\)(L) → 2Br (aq) + I\(_2\)(s)
lll 2F (aq) + CI\(_2\)(g) → 2CI (aq) + F\(_2\)(g)

IV 2F(aq) + Br\(_2\)(l) → 2Br (aq) + F\(_2\)(g)

Bll

Cl and lll

Dlll and lV

View Explanation & Discuss

Question 15

jamb 1989

Gunpower is made from charcoal, sulphur and potassium trioxonitrate (V) The salt in the mixture performs the function of

Aan oxidant

Ba reductant

Ca solvent

Da catalyst

View Explanation & Discuss

Question 16

jamb 1989

Some products of destructive distillation of coal are?

Acarbon (IV) oxide and ethanoic acid

Btrioxocarbonate (IV) acid and methanoic acid

Cproducer gas and water gas

Dcoke and ammoniacal liquor

View Explanation & Discuss

Question 17

jamb 1989

The catalyst used in the contact process for the manufacture of tetraoxosulphate (VI) acid is

Amanganes (IV) oxide

Bmanganese (ll) tetraoxosulphate (VI)

Cvanadium (V) oxide

Diron metal

View Explanation & Discuss

Question 18

jamb 1989

Which of the following represents the balanced equation for the reaction of copper with concentrated trioxonitrate (V) acid?

ACu _(s) + 2HNO _3(aq) → Cu (NO ₃) _2(aq) + H _2(g)

BCu _(s) + 4HNO _3(aq) → Cu (NO ₃) _2(aq) + 2H ₂O ₍₁₎ + 2NO _2(g)

C3Cu _(s) + 8HNO_3(aq) → 3Cu (NO₃)_2(aq) + 4H₂O₍₁₎ + 2NO_(g)

D3Cu_(s) + 4HNO_3(aq) → 3Cu(NO ₃) _2(aq) + 2H ₂O ₍₁₎ + 2NO _(g)

View Explanation & Discuss

Question 19

jamb 1989

The combustion of ethene, C ₂H ₄, is given by the equation C ₂H ₄ + 30 ₂ → 2CO₂ + 2H₂ O; ∆H = - 1428 KJ. If the molar heats of formation of water and carbon (IV) oxide are - 286 kJ and - 396 kJ respectively, calculate the molar heat of formation of ethene in KJ

A- 2792

B+ 2792

C- 64

D+ 64

View Explanation & Discuss

Question 20

jamb 1989

An element, Z froms an anion whose formula is [Z(CN)₆]^y. If Z has an oxidation number of +2, what is the value of y?

A- 2

B- 3

C- 4

D- 5

View Explanation & Discuss

Question 21

jamb 1989

What is discharged at the cathode during the electrolysis of copper (ll) tetraoxosulphate (VI) solution?

ACu ²⁺ only

BH + only

CCu ²⁺ and H

DCu ²⁺ and SO ^2-

View Explanation & Discuss

Question 22

jamb 1989

The same current is passed for the same time through solutions of AgNO₃ and CuSO₄ connected in series. How much silver will be deposited if 1.0 g of copper is produced?
[Cu = 63.5, S = 32, O = 16, Ag = 108, N = 14]

A1.7 g

B3.4 g

C6. 8 g

D13. 6 g

View Explanation & Discuss

Question 23

jamb 1989

An acid and its conjugate base

Acan neutralise each other to form a salt

Bdiffer only by a proton

Cdiffer only by the opposite charges they carry

Dare always neutral substances

View Explanation & Discuss

Question 24

jamb 1989

The substance ZnO dissolves in sodium hydroxide solution and mineral acid solution to give soluble products in each case. ZnO is therefore referred to as

Aan allotropic oxide

Ban amphoteric oxide

Ca peroxide

Da dioxide

View Explanation & Discuss

Question 25

jamb 1989

A solution of calcium bromide contains 20 g dm\(^3\). What is the molarity of the solution with respect to calcium bromide and bromide ions? [Ca = 40, Br = 80]

A0. 1, 0 . 1

B0. 1, 0. 2

C0. 1, 0. 05

D0.05, 0.1

View Explanation & Discuss

Question 26

jamb 1989

Using 50 cm\(^3\) of 1 M potassium hydroxide and 100 cm\(^3\) of 1 M tetraoxosulphate (VI) acid, calculate the respective volumes in cm\(^3\) of base and acid that would be required to produce the maximum amount of potassium tetraoxosulphate (IV) [K = 39, S = 32, O = 16, H = 1]

A50, 50

B25, 50

C50, 25

D25, 25

View Explanation & Discuss

Question 27

jamb 1989

A hydrated salt of formula MSO4.xH2 O CONTAINS 45.3% by mass of water of crystalisation. Calculate the value of x [M = 56, S = 32, O = 16, H = 1 ]

D10

View Explanation & Discuss

Question 28

jamb 1989

Calcium hydroxide is added in the treatment of town water supply to

Akill bacteria in the water

Bfacilitate coagulation of organic particles

Cfacilitate sedimentation

Dimprove the taste of the water

View Explanation & Discuss

Question 29

jamb 1989

The gaseous pollutant sulphur (IV)oxide is most likely to be detected in fairly reasonable quantities in the area around a plant for the

Aextraction of aluminium from bauxite

Bproduction of margarine

Csmelting of copper

Dproduction of chlorine from brine

View Explanation & Discuss

Question 30

jamb 1989

How many valence electrons are contained in the element represented \(^{31}\) \(_{15}\)P?

C15

D31

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