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 301

jamb 2018

What volume of oxygen will remain after reacting 8cm\(^3\) of hydrogen gas with 20cm\(^3\) of oxygen gas?

A10cm\(^3\)

B12cm\(^3\)

C14cm\(^3\)

D16cm\(^3\)

View Explanation & Discuss

Question 302

jamb 2018

The number of electrons in the valence shell of an element of atomic number 14 is?

View Explanation & Discuss

Question 303

jamb 2018

Suitable reagents for the laboratory preparation of nitrogen are

Asodium dioxonitrate(III) and ammonium chloride

Bsodium trioxonitrate(V) and ammonium chloride

Csodium chloride and ammonium trioxonitrate(V)

Dsodium chloride and ammonium di-ozonitrate(III)

View Explanation & Discuss

Question 304

jamb 2018

A quantity of electricity liberates 3.6g of Silver from its salt. What mass of aluminium Will be liberated from its salt by the same quantity of electricity? [Al = 27, Ag = 108].

A2.7g

B1.2g

C0.9g

D0.3g

View Explanation & Discuss

Question 305

jamb 2018

Methanoic acid mixes with water in all proportions and has about the same boiling point as water. Which of the following methods would you adopt to obtain pure water from a mixture of Sand, water and methanoic acid?

AExtractive distillation

BFiltration followed by distillation

CNeutralization with sodium hydroxide followed by distillation

DNeutralization with sodium hydroxide followed by filtration

View Explanation & Discuss

Question 306

jamb 2018

In the preparation of oxygen by heating KCIO\(_3\) , in the presence of MnO\(_2\) only moderate heat is needed because the catalyst acts by \(_2\)

Alowering the pressure of the reaction

Bincreasing the surface area of the reaction

Cincreasing the rate of the reaction

Dincreasing the energy barrier of the reaction

View Explanation & Discuss

Question 307

jamb 2018

Which of the following pairs of substances will react further with oxygen to form a higher oxide?

ACO\(_2\) and H\(_2\)O

BNO and H\(_2\)O

CCO and CO\(_2\)

DSO\(_2\) and NO

View Explanation & Discuss

Question 308

jamb 2018

The boiling of fat and aqueous caustic soda is referred to as

Ahydrolysis

Besterification

Cacidification

Dsaponification

View Explanation & Discuss

Question 309

jamb 2018

In the shown experiment (Fig. 1) the litmus paper will initially

Abe bleached

Bturn green

Cturn red

Dturn blue

View Explanation & Discuss

Question 310

jamb 2018

If 1 litre of 2.2M sulphuric acid is poured into a bucket containing 10 litres of water and the resulting solution mixed thoroughly, the resulting sulphuric acid concentration will be

A2.2M

B1.1M

C0.2M

D0.11M

View Explanation & Discuss

Question 311

jamb 2018

The periodic classification is an arrangement of the elements

Aatomic weights

Bisotopic weights

Cmolecular weights

Datomic numbers

View Explanation & Discuss

Question 312

jamb 2018

Which of the following statements is correct about the periodic table?

AElements in the same period have the same number of valence electrons

BThe valence electrons of the elements in the same period increase progressively across the period

CElements in the same group have the same number of electron shells

DThe non-metallic Properties of the elements tend to decrease across each period

View Explanation & Discuss

Question 313

jamb 2018

On which of the following is the solubility of a gaseous substance dependent?
I. Nature of solvent
II. Nature of solute
III. Temperature
IV. Pressure

AI, II, III and IV

BI and II only

CII only

DIII and IV only

View Explanation & Discuss

Question 314

jamb 2018

A basic postulate of the kinetic theory of gases is that the molecules of a gas move in straight lines between collisions. This implies that

Acollisions are perfectly elastic

Bforces of repulsion exist

Cforces of repulsion and attraction are in equilibrium

Dcollisions are inelastic

View Explanation & Discuss

Question 315

jamb 2018

A correct electrochemical series can be obtained from Na, Ca, Al, Mg, Zn, Fe, Pb, H, Cu, Hg, Ag, Au by interchanging

AAl and Mg

BZn and Fe

CZn and Pb

DPb and H

View Explanation & Discuss

Question 316

jamb 2018

The Consecutive members of an alkane homologous series differ by

ACH

BCH\(_2\)

CCH\(_3\)

DC\(_n\)H\(_n\)

View Explanation & Discuss

Question 317

jamb 2018

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

AHCl\(_{(g)}\)

BNH\(_3\)

CCl\(_2\)

DSO\(_2\)

View Explanation & Discuss

Question 318

jamb 2018

An element used in the production of matches is

Anitrogen

Baluminium

Ccopper

Dsulphur

View Explanation & Discuss

Question 319

jamb 2018

According to the Kinetic Theory an increase in temperature causes the kinetic energy of particles to

Adecrease

Bincrease

Cbe zero

Dremain constant

View Explanation & Discuss

Question 320

jamb 2018

To what temperature must a gas at 273k be heated in order to double both its volume and pressure?

A298K

B546K

C819K

D1092K

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