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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.

47 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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Past Questions

47 questions

Question 1 of 20 47 total questions

Question 11

jamb 1986

Which of the following is used as an 'anti-knock' in automobile engines?

ATetramethyl silane

BLead tetra-ethyl

CGlycerol

Dn-heptane

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Question 12

jamb 1986

Which of the following is NOT correct test for the named organic compound in each case?

AButanoic acid solution gives effervescence with Na₂CO₃ solution

BGlucose when reacted with Na₂CrO₄ at 0°C will show immediate discharge of colour

CWhen but-2-ene is reacted with dilute solution of KMnO₄ the purple colour of KMnO is discharged readily even room temperature

DWhen butan-2-ol is boiled with butanoic acid with a drop of concentrated H₂SO₄ a sweet smelling liquid is produced

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Question 13

jamb 1986

How will a metal X, which reacts explosively with air and with dilute acids be best extracted from its ores?

AElectrolysis of solution of its salts

BDecomposition of its oxides

CDisplacement from solution by an alkali metal

DElectroiysis of fused salt

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Question 14

jamb 1986

Which of the following compounds would give lilac flame coloration and a white precipitate with acidified barium chloride solution?

AKCI

BNaNO₃

CK₂SO₄

DCaSO₄

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Question 15

jamb 1986

A white solid suspected to be lead trioxonitrate (V) zinc trioxocarbonate (IV) or calcium trioxocabonate (IV) was heated strongly. Its residue which was yellow when hot and white when cold is?

Alead (II) oxide

Bcalcium oxide

Czinc oxide

Dlead nitrate

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Question 16

jamb 1986

Which of the following does NOT contain aluminium as component?

AOver-head cables

BDuralumin

CContainer for caustic soda

DContainer for nitric acid

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Question 17

jamb 1986

The iron (III) oxide impurity in bauxite can be removed by?

AFractional crystallization in acid solution

Bdissolution in sodium hydroxide and filtration

Cextraction with concentrated ammonia and reprecipitation

Delectroysis of molten mixture

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Question 18

jamb 1986

What are the values of x, y and z respectively in the equation: xCu + yHNO₃ → xCu(NO₃)₂ + 4H₂O + zNO?

A4: 1: 2

B3:8:2

C2:8:3

D8:3:2

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Question 19

jamb 1986

Ammonia gas is normally dried with?

Aconcentrated sulphuric acid

Bquicklime

Canhydrous calcium chloride

Dmagnesium sulphate

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Question 20

jamb 1986

A substance Z reacts with NaOH to give salt and water only. When Z is treated with dilute HCl, a gas is evolved which gives a yellow suspension on passing into concentrated H₂SO₄. Substance Z is?

ANaHS

BNa₂SO₃

CNa₂S

DNaHSO₃

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Question 21

jamb 1986

When chlorine is passed into water and subsequently exposed to sunlight, the gas evolved is?

AHCl

BHOCl

CO₂

DCl₂O

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Question 22

jamb 1986

Which of the following sulphides is insoluble in dilute HCl?

ANa₂S

BZnS

CCuS

DFeS

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Question 23

jamb 1986

Which of the following metals does NOT form a stable trioxocarbonate (IV)?

AFe

BAl

CZn

DPb

Enone of the options is correct

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Question 24

jamb 1986

In the course of an experiment, two gases X and Y were produced. X turned wet lead ethanoate to black and Y bleached moist litmus paper. What are the element(s) in each of the gases X and Y respectively?

AH and S;Cl

BH and O;Cl

CH and S;C and O

DH and Cl;S and O

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Question 25

jamb 1986

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

ANO and H₂O

BCO and CO₂

CSO₂ and NO

DCO₂ and H₂O

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Question 26

jamb 1986

Oxygen-demanding waste are considered to be a water pollutant because they?

Adeplete oxygen which is necessary for the survival of aquatic organism

Bincrease oxygen which is necessary for survival of aquatic organism

Cincrease other gaseous substances which are necessary for the survival of aquatic organisms

Ddeplete other gaseous species which is necessary for the survival of aquatic organisms

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Question 27

jamb 1986

The exhaust fumes from a garage in a place that uses petrol of high sulphur content are bound to contain?

ACO and SO₃

BCO and SO₂

CCO,SO₂ and SO₃

DCO and H₂S

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Question 28

jamb 1986

When steam is passed through red hot carbon, which of the following are produced?

AHydrogen oxygen and carbon (IV) oxide

BHydrogen and carbon (IV) oxide

CHydrogen and carbon (II) oxide

DHydrogen and trioxocarbonate (IV) acid

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Question 29

jamb 1986

The reaction Mg + H₂O → MgO + H₂ takes place only in the presence of?

Aexcess Mg ribbon

Bexcess cold water

Cvery hot water

Dsteam

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Question 30

jamb 1986

The approximate volume of air containing 10cm³ of oxygen is?

A20 cm³

B25 cm³

C50 cm³

D100 cm³

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