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 1241

jamb 1978

An example of an alcohol is

ACCl₄

BCH₃COOH

CCHCl₃

DC₂H₆

ECH₃OH

View Explanation & Discuss

Question 1242

jamb 1978

When ammonia and hydrogen ion bond together to form ammonium ion, the bond formed is called

Aionic bond

Belectrovalent bond

Ccovalent bond

Dco-ordinate bond

Ehydrogen bond

View Explanation & Discuss

Question 1243

jamb 1978

Which of the following is not a member of the homologous series of the paraffins (alkanes)?

AC₃H₈

BC₅H₁₂

CC₇H₁₆

DC₁₅H₃₂

EC₂₄H₄₈

View Explanation & Discuss

Question 1244

jamb 1978

Which of the following reactions does not take place in the smelting of iron in a blast furnace?

A\(CaCO_{3(s)} → CaO_{(s)} + (CO_{2(g)}\)

B\(C_{(s)} + O_{2(g)} → CO_{2(g)}\)

C3\(Fe{(s)} + 2O_{2(g)} → FeO_{4(s)}\)

D\(SiO_{2(s)} + CaO_{(s)} → CaSiO_{3(s)}\)

E\(CO_{2(g)} + C_{(s)} → 2CO_{(g)}\)

View Explanation & Discuss

Question 1245

jamb 1978

Which of the following gases may not be dried with concentrated sulphuric acid?

AHCl

BN₂

CCl₂

DSO₂

ENH₃

View Explanation & Discuss

Question 1246

jamb 1978

Brass and bronze are both metallic alloys. Which of the following constituents is common to both alloys?

ATin

BZinc

CCopper

DLead

EAluminium

View Explanation & Discuss

Question 1247

jamb 1978

If 30cm\(^3\) of oxygen diffuses through a porous pot in 7 seconds, how long will it take 60cm\(^3\) of chlorine to diffuse through the same pot, if the vapour densities of oxygen and chlorine are 16 and 36 respectively?

A9.3 sec

B14 sec

C21 sec

D28 sec

E30.3 sec

View Explanation & Discuss

Question 1248

jamb 1978

The IUPAC names of the compounds CH3COOH and CH2=CH2 are respectively;

Aacetic acid and ethene

Bmethanoic acid and ethene

Cmethanoic acid and ethylene

Dethanol and ethene

Eacetic acid and ethylene

View Explanation & Discuss

Question 1249

jamb 1978

The reaction between an organic acid and an alcohol in the presence of an acid catalyst is known as;

Asaponification

Bdehydration

Cesterification

Dhydrolysis

Ehydration

View Explanation & Discuss

Question 1250

jamb 1978

During the electrolysis of copper II sulphate between platinum electrodes, if litmus solution is added to the anode compartment,

Athe litmus turns blue but no gas is evolved

Bthe litmus turns blue and oxygen is evolved

Cthe litmus turns blue and hydrogen is evolved

Dthe litmus turns red and oxygen is evolved

Ethe litmus turns red and then becomes colourless

View Explanation & Discuss

Question 1251

jamb 1978

A sample of hard water contains some calcium sulphate and calcium hydrogen carbonate. The total hardness may therefore be removed by

Aboiling the water

Badding excess calcium hydroxide

Cadding a calculated amount of calcium hydroxide

Dadding sodium carbonate

Eadding magnesium hydroxide

View Explanation & Discuss

Question 1252

jamb 1978

Which of the following metals cannot replace hydrogen from water or steam?

ASodium

BMagnesium

CIron

DCalcium

ECopper

View Explanation & Discuss

Question 1253

jamb 1978

When each of the nitrates of Potassium, Magnesium and iron is heated,

Aall the nitrates decompose to their oxides

Bthe nitrate of magnesium gives the nitrite and oxygen

Cthe nitrates of magnesium and iron give the oxides

Dthe nitrate of iron gives the nitrite and oxygen

Ethe nitrate of the magnesium is not decomposed

View Explanation & Discuss

Question 1254

jamb 1978

The pH of four solutions W, X, Y, Z are 4, 6, 8, 10 respectively, therefore

Anone of these solutions is acidic

Bthe pH of Y is made more acidic by addition of distilled water

CZ is the most acidic solution

DW is the most acidic solution

EX is neutral

View Explanation & Discuss

Question 1255

jamb 1978

When large hydrocarbon molecules are heated at high temperature in the presence of a catalyst to give smaller molecules, the process is known as

Adisintegration

Bpolymerization

Ccracking

Ddegradation

Edistillation

View Explanation & Discuss

Question 1256

jamb 1978

When heat is absorbed during a chemical reaction, the reaction is said to be

Athermodynamic

Bexothermic

Cisothermal

Dendothermic

Ethermostatic

View Explanation & Discuss

Question 1257

jamb 1978

When air which contains the gases Oxygen, nitrogen, carbondioxide, water vapour and the rare gases, is passed through alkaline pyrogallol and then over quicklime, the only gases left are?

Anitrogen and carbondioxide

Bthe rare gases

Cnitrogen and oxygen

Dnitrogen and the rare gases

Enitrogen, carbondioxide and the rare gases

View Explanation & Discuss

Question 1258

jamb 1978

The oxidation state of chlorine in potassium chlorate is?

A+1

B+2

C+3

D+5

E+7

View Explanation & Discuss

Question 1259

jamb 1978

An element X forms the following compounds with chlorine; XCl4, XCl3, XCl2. This illustrates the

Alaw of multiple proportions

Blaw of chemical proportions

Claw of simple proportions

Dlaw of conservation of mass

Elaw of definite proportions

View Explanation & Discuss

Question 1260

jamb 1978

Elements P, Q, R, S have 6, 11, 15, 17 electrons respectively, therefore,

AP will form an electrovalent bond with R

BQ will form a covalent bond with S

CR will form an electrovalent bond with S

DQ will form an electrovalent bond with S

EQ will form a covalent bond with R

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