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.

1,623 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

1,623 questions

Question 1 of 20 1,623 total questions

Question 181

waec 2018

Analysis of a hydrocarbon shows that it contains 0.93g of Carbon per gram of the compound. The mole ratio of carbon to hydrogen in the compound is [H = 1.0, C=12.0]

A1:1

B1:2

C2:1

D2:3

View Explanation & Discuss

Question 182

waec 2018

Which of the following statements is true about ionic radius? Ionic radius

Aincreases as nuclear charge increases

Bdecreases as nuclear charge increases

Cdecreases as nuclear charge decreases

Dremains constant as nuclear charge increases

View Explanation & Discuss

Question 183

waec 2018

Which of the following methods can be used to seperate blood cells from plasma?

ACentrifugation

BFiltration

CChromatography

DDistillation

View Explanation & Discuss

Question 184

waec 2018

The change in the oxidation state of iron in the reaction represented by the equation: \(2FeCl_{3} + H_{2}S \to 2FeCl_{2} + 2HCl + S\) is

A+2 to +3

B0 to +2

C+3 to +2

D+3 to 0

View Explanation & Discuss

Question 185

waec 2018

The empirical formula of a compound containing 0.067mol Cu and 0.066mol O is [Cu = 63.5, O = 16]

A\(Cu_{2}O\)

B\(CuO\)

C\(CuO_{2}\)

D\(CuO_{4}\)

View Explanation & Discuss

Question 186

waec 2018

When zinc is added to AgNO\(_{3}\) solution, crystals of silver forms on the zinc surface. This indicates that zinc is

Aoxidised

Breduced

Cdecomposed

Ddissociated

View Explanation & Discuss

Question 187

waec 2018

The strength of metallic bonds depends on the

Acharge density of the atoms

Bductility of the metal

Cnumber of valence electrons

Dtotal number of electrons in the atom

View Explanation & Discuss

Question 188

waec 2018

How many atoms are contained in 0.2moles of nitrogen? \([N_{A} = 6.02 \times 10^{23}]\)

A\(1.20 \times 10^{23}\)

B\(2.41 \times 10^{23}\)

C\(3.62 \times 10^{23}\)

D\(4.82 \times 10^{23}\)

View Explanation & Discuss

Question 189

waec 2018

When chlorine is passed through a sample of water, the pH of the water sample would be

A< 7

B> 7

C= 7

View Explanation & Discuss

Question 190

waec 2018

One of the criteria for confirming the purity of benzene is to determine its

Aheat capacity

Bboiling point

Cmass

Dcolour

View Explanation & Discuss

Question 191

waec 2018

Which of the following CANNOT be an empirical formula?

A\(CH\)

B\(CH_{2}\)

C\(P_{2}O_{5}\)

D\(N_{2}O_{4}\)

View Explanation & Discuss

Question 192

waec 2018

\(Cu\) and \(HNO_{3}\) are not suitable for preparing hydrogen gas because of their

Areactivity and oxidation respectively

Bconductivity and corrosiveness respectively

Cmelting point and reduction respectively

Delectronegativity and solubility respectively

View Explanation & Discuss

Question 193

waec 2018

Consider the following reaction equation: \(2HCl + Ca(OH)_{2} \to CaCl_{2} + H_{2}O\). What is the volume of 0.1\(moldm^{-3}\) HCl that would completely neutralize 25\(cm^{3}\) of 0.3\(moldm^{-3}\) Ca(OH)\(_{2}\)?

A150\(cm^{3}\)

B75\(cm^{3}\)

C30\(cm^{3}\)

D25\(cm^{3}\)

View Explanation & Discuss

Question 194

waec 2018

Which of the following statements best explains the difference between a gas and a vapour?

AUnlike gases, vapours are liquids at room temperature

BUnlike gases, vapour can easily be condensed into liquids

CUnlike gases, vapour is readily converted into solids

DVapours are generally denser than gases

View Explanation & Discuss

Question 195

waec 2018

The diagram above illustrates a conical flask containing water and ice. Which of the following is correct about the diagram?

AThe water is at lower temperature than the ice

BEnergy is absorbed when the ice changes to water

CEnergy is released when the ice changes to water

DThe water molecules vibrate about a fixed point

View Explanation & Discuss

Question 196

waec 2018

The position of equilibrium in a reversible reaction is affected by

Aparticle size of the reactants

Bvigorous stirring of the reaction mixture

Cpresence of a catalyst

Dchange in concentration of the reactants

View Explanation & Discuss

Question 197

waec 2018

The following factors would contribute to environmental pollution except

Aproduction of ammonia

Bmanufacture of cement

Cphotosynthesis

Dcombustion

View Explanation & Discuss

Question 198

waec 2018

The most suitable substance for putting out petrol fire is

Awater

Bcarbon(IV) oxide

Cfire blanket

Dsand

View Explanation & Discuss

Question 199

waec 2018

The number of Hydrogen ions in 1.0\(dm^{3}\) of 0.02\(moldm^{-3}\) tetraoxosulphate(VI) acid is \([N_{A} = 6.02 \times 10^{23}]\)

A\(1.2 \times 10^{22}\)

B\(1.2 \times 10^{23}\)

C\(2.4 \times 10^{22}\)

D\(2.4 \times 10^{23}\)

View Explanation & Discuss

Question 200

waec 2018

Stainless steel is an alloy comprising of

AFe and C

BFe and Ni

CFe, C and Ni

DFe, C and Al

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