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.

4,306 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

4,306 questions

Question 1 of 20 4,306 total questions

Question 1021

jamb 2008

The product obtained when a mixture of benzene vapour and hydrogen are passed over nickel catalyst at 180ºC is

Acyclohexane

Bcyclopentane

Cn- hexane

Dn - pentane

View Explanation & Discuss

Question 1022

jamb 2008

Reduction of alkanones with LialH4 produces

Aprimary alkanols

Bsecondary alkanols

Ctertiary alkanols

Dpolyhydric alkanols

View Explanation & Discuss

Question 1023

jamb 2008

Reduction of nitroalkanes, nitrites and amides is a route for the preparation of

Aamines

Balkenes

Cpolymers

Ddetergents

View Explanation & Discuss

Question 1024

jamb 2008

A red precipitate of copper (I) carbide is formed when ammonium solution of copper (I) chloride is introduced into

ACH₂ = CH - CH₂ - CH₃

BCH₃ CH₂ - C ≡ CH

CCH₃ CH₂ CH₂ CH₃

DCH₃ - C C - CH₃

View Explanation & Discuss

Question 1025

jamb 2008

A hydrocarbon X with a molar mass of 26 consists of 92.3% carbon. What is its molecular formular?

AC₂H₂

BC₃H₃

CC₄H₄

DC₅H₅

View Explanation & Discuss

Question 1026

jamb 2008

The IUPAC nomenclature for the structure above is

A2, 3 - dichloro - 4, 4, 5 - trimethyl pent - 2 - ene

B4, 5 - dichloro - 2, 3 - dimethyl hex - 2 - ene

C2, 3 - dichloro - 4, 4 - dimethyl hex - 2- ene

D2, 3 dichloro - 2, 2 - dimethyl hex - 2 - ene

View Explanation & Discuss

Question 1027

jamb 2008

If glucose is heated with concentration tetraoxosulphate (VI) acid, it will be dehydrated to

Acarbon

Bcarbon (IV) oxide

Cethene

Dethanol

View Explanation & Discuss

Question 1028

jamb 2008

If the silver mirror test is positive, it indicates the presence of an

Aalkyne

Balkanol

Calkanone

Dalkanal

View Explanation & Discuss

Question 1029

jamb 2008

The type of isomerism shown by cis- and trans- isomers is

Aoptical isomerism

Bpositional isomerism

Cfunctional isomerism

Dgeometrical isomerism

View Explanation & Discuss

Question 1030

jamb 2008

The most common ores of iron include

Ahaematite, malachite and limonite

Bchalcocite, calamine and bornite

Cmagnetite, haematite and limonite

Dmagnetite, chalcocite and bornite

View Explanation & Discuss

Question 1031

jamb 2008

which of the following gives a precipitate when treated with NaOH solution?

AAlCl₃

BNH₄Cl

CNa₂CO₃

DCH₃COONa

View Explanation & Discuss

Question 1032

jamb 2008

Leads is used for making bullets and lead shots because of its

Aresistance to corrosion

Blow melting point

Chigh density

Dflexibility

View Explanation & Discuss

Question 1033

jamb 2008

When a solution of ammonium trioxocarbonate (IV) is added to a solution of an unknown salt, a white precipitate which is soluble in dilute hydrochloric acid but insoluble in ethanoic acid is formed. This indicates the presence of

ACa²⁺

BNa⁺

CZn²⁺

DK⁺

View Explanation & Discuss

Question 1034

jamb 2008

Which of the following compounds of trioxonitrate (V) will decompose to give dinitrogen (i) oxide and water when heated?

ANaNO₃

BZn(NO₃)₂

CCu(NO₃)₂

DNH₄NO₃

View Explanation & Discuss

Question 1035

jamb 2008

The substance that is used in the steel industry for the removal of carbon, sulphur and phosphorus impurities from pig iron is

Aoxygen

Bchlorine

Cnitrogen

Dhydrogen

View Explanation & Discuss

Question 1036

jamb 2008

The rate of a reaction usually decreases with a decrease in the concentration of reactants because

Akinetic energy decrease

Btemperature increase

Cspeed increases

Dreactants collision decrease

View Explanation & Discuss

Question 1037

jamb 2008

A catalyst speeds up the rate of chemical reaction by

Ataking part in the reaction

Bincreasing the activation energy of the reaction

Clowering the activation energy of the reaction

Dincreasing the heat content

View Explanation & Discuss

Question 1038

jamb 2008

Which of the following reaction is endothermic?

AC_(s) + O_2(g) → CO_2(g)

BCaO_(s) + H₂O_(l) → Ca(OH)_2(s)

CC_(s) + H₂O_(g) → CO_(g) + H_2(g)

DHCl_(aq) + NaOH_(aq) → NaCl_(aq) + H₂O_(l)

View Explanation & Discuss

Question 1039

jamb 2008

\(NH_{3(g)} + HCl_{(g)} → NH_4Cl_{(s)}\)
The entropy change in the system above is

Apositive

Bzero

Cnegative

Dindeterminate

View Explanation & Discuss

Question 1040

jamb 2008

If a given quantity of electricity liberates 0.65g of Zn2+, what amount of Hg2+ would be liberated by the same quantity of current?
[Zn = 65, Hg = 201]

A1.00g

B2.01g

C4.02g

D8.04g

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