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.

50 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

50 questions

Question 1 of 20 50 total questions

Question 1

jamb 1983

In the experiment above, a current was passed for 10 minutes, and 0.63g of copper was found to be deposited on the cathode of CuSO4 cells. The weight of silver deposited on the cathode of AgNO3 cell during the same period would be? [Cu = 63, Ag = 108]

A0.54g

B1.08g

C1.62g

D2.16g

E3.24g

View Explanation & Discuss

Question 2

jamb 1983

In the above experiment, the litmus paper will initially

Abe bleached

Bturn green

Cturn red

Dturn blue

Eturn black

View Explanation & Discuss

Question 3

jamb 1983

30 cm³ of 0.1 M Al (NO₃)₃ SOLUTION IS RECTED WITH 100cm³ of 0.15M of NaOH solution. Which reactant is in excess, and by now much ?

ANaOH solution by 70 cm³

BNaOH solution, by 60 cm³

CNaOH solution by 40 cm³

DAl(NO₃)₃ solution by 20 cm³

EAl(NO₃)₃ solution by 10 cm³

View Explanation & Discuss

Question 4

jamb 1983

\(Zn + H_2 SO_4 → ZnSO_4 + H_2\)

in the above reaction, how much zinc will be left undissolved if 2.00g of zinc is treated with 10cm^3 of 1.0 M of \(H_2SO_4\)?
[Zn =65, s = 32, O = 16, H = 1]

A1.35g

B1.00g

C0.70g

D0.65g

E0.00g

View Explanation & Discuss

Question 5

jamb 1983

zn + 2HCl → ZnCl₂ + H₂

The rate of the above reaction will be greatly increased if

Athe zinc is in the powered form

Ba greater volume of the acid is used

Ca smaller volume of the acid is used

Dthe reaction vessel is immersed in an ice-bath

Ethe zinc is in the form of pellets

View Explanation & Discuss

Question 6

jamb 1983

The equilibrium reaction between copper (l) chloride and chlorine at 25^oC and 1 atmosphere is represented by the equation:
2CuCl +Cl₂ ⇌ 2 CuCl₂ ∆H = - 166 KJ. Which of the following statements is TRUE for the reaction, pressure remaining constant?

Amore CuCl is formed at 40^oC

Bmore CuCl₂ is formed at 10^oC

CLess CuCl₂ is formed at 10^oC

Dthere is no change in the amount of CuCl₂ formed at 40^oC and10^oC

Emore CuCl is consumed at 40^oC

View Explanation & Discuss

Question 7

jamb 1983

When sodium dioxonitrate (lll) (NaNO₂) dissolves in water, ∆H is positive. The process of dissolution is

Aexothermic

Bendothermic

Cisothermal

Disomeric

Ehygroscopic

View Explanation & Discuss

Question 8

jamb 1983

Which of the following statements is FALSE?

ACopper (ll) ion can be reduced to copper (l) ion by hydrochloric acid and zinc

BSodium metal dissolves in water giving oxygen

CNitrogen is insoluble in water

DCarbondioxide is soluble in water

Elead has a higher atomic weight than copper

View Explanation & Discuss

Question 9

jamb 1983

Liquid X, reacts with sodium trioxocarbonate (IV) (Na₂CO₃) to give a gas which turns calcium chloride solution milky X is

ANa₂SO₄(aq)

BKl (aq)

Can alkali

Dan acid

Ea hydrocarbon

View Explanation & Discuss

Question 10

jamb 1983

A jet plane carrying 3,000 kg of ethane burns off all the gas forming water and carbondioxide. if all the carbondioxide is expelled and all the water formed is condensed and kept on board the plane, then the gain in weight is

A1,800 kg

B900 kg

C600 kg

D2, 400 kg

E1, 200 kg

View Explanation & Discuss

Question 11

jamb 1983

Which of the following is a neutralization reaction?

AAddition of sodium chloride solution to potassium chloride solution

BAddition of trioxonitrate (V) acid (nitric acid) to distilled water

CAddition of trioxonitrate (V) acid (nitric acid) to tetraoxosulphate (IV) acid (sulphuric acid)

DAddition of trioxonitrate (V) acid (nitric acid) to potassium trioxonitrate (V) (potassium nitrate) solution

EAddition of trioxonitrate (V) acid (nitric acid) to potassium hydroxide solution

View Explanation & Discuss

Question 12

jamb 1983

The mass of an atom is determined by

Aits ionization potential

Bits electrochemical potential

Cthe number of protons and electrons

Dthe number of neutrons and protons

Ethe number of neutrons and electrons

View Explanation & Discuss

Question 13

jamb 1983

Which of the following solutions will give a white precipitate with barium chloride solution and a green flame test?

ANa₂SO₄

BCuSO₄

CCaSO₄

DCaCI₂

E(NH₄)₂SO₄

View Explanation & Discuss

Question 14

jamb 1983

A gas that can behave as a reducing agent towards chlorine and as an oxidizing agent toward hydrogen sulphide is

AO₂

BNO

CSO₂

DNH₃

ECO₂

View Explanation & Discuss

Question 15

jamb 1983

The cracking process is very important in the petroleum industry because it.

Agives purer products

Byields more lubricants

Cyields more engine fuels

Dyields more asphalt

Eyields more candle wax

View Explanation & Discuss

Question 16

jamb 1983

3. 06 g of a sample of potassium trioxochlorate (V) (KCIO\(_3\)) was required to make a saturated solution with 10cm\(^3\) of water at 25°C. The solubility of the salt at 25°C is [K =39, Cl = 35.5, O = 16]

A5.0 moles dm³

B3.0 moles dm³

C2.5 moles dm³

D1.0 molesv

E0.5 moles dm³

View Explanation & Discuss

Question 17

jamb 1983

2.5 g of a hydrate barium salt gave on heating, 2.13 g of the anhydrous salt. Given that the relative molecular mass of the of the anhydrous salt is 208, the number of molecules of water of crystallization of the barium salt is

A10

View Explanation & Discuss

Question 18

jamb 1983

Increasing the pressure of a gas

Alowers the average kinetic energy of the molecules

Bdecreases the density of the gas

Cdecreases the temperature of the gas

Dincreases the density of the gas

Eincreases the volume of the gas

View Explanation & Discuss

Question 19

jamb 1983

Which of the following separation processes is most likely to yield high quality ethanol (>95%) from palm wine?

AFractional distillation without a dehydrant

Bsimple distillation with a dehydrant

Cfractional distillation with a dehydrant

Dcolumn chromatography

Eevaporation

View Explanation & Discuss

Question 20

jamb 1983

In the preparation of some pure crystals of Cu (NO₃)₂ starting with CuO, a student gave the following statements as steps he employed. Which of these shows a flaw in his report ?

Asome CuO was reacted with excess dilute H₂SO₄

Bthe solution was concentrated

Cwhen the concentrate was cooled, crystals formed were removed by filtration

Dthe crystals were washed with very little cold water

Ethe crystals were then allowed to dry

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