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Chemistry Past Questions

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2,505 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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2,505 questions

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Question 31

jamb 2025

In a series of solutions with pH of 2.5, 3.5, 7.0 and 8.0, which is likely to turn red moist litmus paper blue?

A3.5

B8.0

C2.5

D7.0

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Question 32

jamb 2025

The correct arrangement of gases in the order of increasing rate of diffusion is

[H = 1, C = 12, N = 14, O = 16, S = 32]

ACO\(_2\), H\(_2\), SO\(_2\), CO

BSO\(_2\), O\(_2\), NH\(_3\), H\(_2\)

CNH\(_3\), NO\(_2\),N\(_2\), CO\(_2\)

DCO\(_2\), NH\(_3\), O\(_2\), SO\(_2\)

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Question 33

jamb 2025

Mg + Pb\(^{2+}\) → Mg\(^{2+}\) + Pb

What is the cell notation for the cell reaction above?

AMgIPb\(^{2+}\)IIMg\(^{2+}\)IPb

BMgIMg\(^{2+}\)IIPbIPb\(^{2+}\)

CMgIMg\(^{2+}\)IIPb\(^{2+}\)IPb

DMgIMg\(^+\)IIPbIPb\(^+\)

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Question 34

jamb 2025

A molecule with a polar covalent bond between atoms exhibits

Aunequal sharing of electron pair

Bequal sharing of electron pair

Cequal sharing of electron lone pair

Dunequal sharing of electron lone pair

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Question 35

jamb 2025

An atom of element with the configuration 1S\(^2\)2S\(^2\)2P\(^6\)3S\(^2\)3P\(^5\) is likely to belong to

Agroup 7

Bgroup 5

Cgroup 2

Dgroup 3

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Question 36

jamb 2025

When a sample of air is passed through alkaline pyrogalol, potash and finally through U-tube containing fused calcium chloride, the components of air left unabsorbed are

Anitrogen and carbon(IV)oxide

Bnoble gases and carbon(IV)oxide

Cnoble gases and nitrogen

Dnoble gases, nitrogen and carbon(IV) oxide

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Question 37

jamb 2025

An example of a physical change is

Aaddition of water to calcium oxide

Bcorrosion of iron

Cdissolving sodium chloride in water

Dburning of charcoal

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Question 38

jamb 2025

Mg\(_{(s)}\) + 2HCl\(_{(aq)}\) → MgCl\(_2\)\(_{(aq)}\) + H\(_2\)\(_{(g)}\)

In the reaction above, magnesium is a reducing agent because

Aoxidized

Breduced

Ca metal

Da solid

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Question 39

jamb 2025

The type of bond between copper(II) tetraamine and chlorine in [Cu(NH\(_3\))\(_4\)]Cl\(_2\)

Adative

Bvan der waals

Cionic

Dcovalent

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Question 40

jamb 2025

In the laboratory preparation of oxygen using potassium trioxochlorate(V), tetraoxomanganate (VII), usually not recommended in modern laboratory because

Ait forms explosive mixture with carbonaceous materials

Bit is explosive.

Cit reacts with the catalyst

Dit is hazardous

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Question 41

jamb 2025

CH\(_3\)C ≡ CCH(CH\(_3\))\(_2\)

The IUPAC nomenclature of the compound above is

A3-ethyl but-2-yne

B4-methylpent-2-yne

C2-ethyl but-2-yne

D2-methyl pent-2-yne

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Question 42

jamb 2025

The nitrogenous compound in dead materials in the soil is converted to

Aammonia

Btrioxonitrate(V)

Cammonium salts

Ddioxonitrate(III)

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Question 43

jamb 2025

The empirical mass of C\(_6\)H\(_{12}\)O\(_6\) is

[H =1, C = 12, O = 16]

A90

B180

C45

D30

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Question 44

jamb 2025

Which of the following statements is false about hard water?

AHelps animals to build strong teeth

BCannot be supplied in pipes made of leads

CTastes better than soft water

DHelps animals to build strong bones.

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Question 45

jamb 2025

The gas that is commonly used to demonstrate the fountain experiment is

Ahydrogen chloride

Bhydrogen sulphide

Cdinitrogen(I) oxide

Dnitrogen(II) oxide

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Question 46

jamb 2025

From the graph, it can be inferred that

Athe solubility of X and Y is the same at all temperature

Bthe solubility of X, Y and Z is temperature dependent

Csolubility of Z increases as temperature increases

Dsolubility of Y increases steadily as temperature increases

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Question 47

jamb 2025

Which of the following has the highest boiling point?

ACH\(_3\)CH\(_2\)OH

BCH\(_3\)CH\(_2\)CH\(_2\)Cl

CCH\(_3\)CH\(_2\)CH\(_2\)CH\(_2\)CH\(_2\)CH\(_3\)

DCH\(_3\)CH\(_2\)CH\(_2\)OH

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Question 48

jamb 2025

A metal that can be found in the free state in nature is

Asilver

BZinc

CIron

Dcopper

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Question 49

jamb 2025

If a gold bar and a silver bar are tied together firmly and left for years, some of the gold particles will be found in the silver bar due to

ABrownian movement

Bdiffusion

Cdisplacement

Dosmosis

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Question 50

jamb 2025

Carbohydrates can generally be represented by the general formula C\(_x\)(H\(_2\)O)\(_y\), for fructose the value for "X" is

B12

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