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Chemistry Past Questions

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75 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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Past Questions

75 questions

Question 1 of 20 75 total questions

Question 21

jamb 1995

Aromatic and aliphatic hydrocarbons can be distinguished from each other by the?

Aaction of bromine

Buse of polymerization reaction

Caction of heat

Duse of oxidation reaction

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Question 22

jamb 1995

Which of the following pairs has compounds that are isomers?

APropanal and propanone

BEthanoic acid and ethylmethanoate

CEthanoic acid and ethane-1, 2-diol

D2-methylbutane and 2, 2-dimethylbutane

View Explanation & Discuss

Question 23

jamb 1995

CHCl₃ + Cl₂ → HCl + CCl₄. The reaction above is an example of?

Aan addition reaction

Ba substitution reaction

Ca chlorination reaction

Da condensation reaction

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Question 24

jamb 1995

Group 1 A metals are not found free in nature because they?

Aare of low melting and boiling points

Bhave weak metallic bonding

Cconduct electricity and heat

Dare very reactive

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Question 25

jamb 1995

Which of the following compounds will impart a brick-red colour to a non-luminious bunsen flame?

ANaCl

BLiCl

CCaCl₂

DMgCl₂

View Explanation & Discuss

Question 26

jamb 1995

In the extraction of iron in the blast furnace, limestone is used to?

Arelease CO₂ for the reaction

Breduce the iron ore

Cincrease the strenght of the iron

Dremove impurities

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Question 27

jamb 1995

Which of the following ions will give a white precipitate with aqueous NaOH and soluble in excess of the base?

ACa²⁺

BMg²⁺

CZn²⁺

DCu²⁺

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Question 28

jamb 1995

A gas that will turn orange potassium heptaoxodichromate (lV) solution to clear green is?

Asulphur (lV) oxide

Bhydrogen sulphide

Csulphide (lV) oxide

Dhydrogen chloride

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Question 29

jamb 1995

Sulphur exists in six forms in the solid state. This property is known as?

Aisomerism

Ballotropy

Cisotopy

Disomorphism

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Question 30

jamb 1995

In the industrial production of hydrogen from natural gas, carbon (IV) oxide produced along with the hydrogen is removed by?

Awashing with water under pressure

Bpassing the mixture into lime water

Cusing ammoniacal copper (l) chloride

Ddrying over phoshorus (V) oxide

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Question 31

jamb 1995

Which of the following equilibria is shifted to the right as a result of an increase in pressure?

AH_2(g) + I_2(g) 2HI_(g)

B2NO_2(g) N₂O_4(g)

CPCl_5(s) PCl_3(s) + Cl_2(g)

D2O_3(g) 3O_2(g)

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Question 32

jamb 1995

Which of the following processes leads to increase in entropy?

AMixing a sample of NaCl and sand

BCondensation of water vapour

CBoiling a sample of water

DCooling a saturated solution

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Question 33

jamb 1995

If an equilibrium reaction has ∆H < O, the reaction will proceed favorably in the forward reaction at?

Alow temperatures

Bhigh temperatures

Call temperatures

Dall pressures

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Question 34

jamb 1995

Cr\(_2\)O\(_7\)\(^{2-}\)(aq) + 14H\(^+\)(aq) + 6l\(^-\)(aq) → 2Cr\(^{3+}\)(aq) + 3l(g) + 7H\(_2\)O(I).
The change in the oxidation number of oxygen in the equation above is?

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Question 35

jamb 1995

Which of the following is a redox reaction?

AKCI_(aq) + H₂SO_4(aq) → KHSO_4(aq) + HCI_(aq)

B2FeBr_2(aq) + Br_4(aq) → 2FeBr_3(aq)

C3AgNO_(aq) + FeCl_3(aq) → 3AgCl_(aq) + Fe(NO₃)_3(aq)

DH₂CO_3(aq) → H₂O_(I)2- + CO_2(g)

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Question 36

jamb 1995

2CL^-_(aq) → CI_2(g) + 2e^-(aq). The above half-cell reaction occuring at the anode during the electrolysis of dilute ZnCI₂ solution is?

Aionization

Boxidation

Creduction

Drecombination

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Question 37

jamb 1995

How many moles of copper would be deposited by passing 3F of electricity through a solution of copper (II) tetraoxosulpohate (IV)?

(F = 96 500 C mol^-)

A0.5

B1.0

C1.5

D3.0

View Explanation & Discuss

Question 38

jamb 1995

In the process of silver-plating a metal M, the metal M is the?

Aanode and a direct current is used

Bcathode and an alternating current is used

Canode and an alternating current is used

Dcathode and a direct current is used

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Question 39

jamb 1995

Neutralization involves a reaction between H₃O⁺ and?

ACI^-

BOH^-

CNO₃^-

DCO₃^2-

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Question 40

jamb 1995

In general, an increase in temperature increases the solubility of a solute in water because?

Amore solute molecules collide with each other

Bmost solutes dissolve with the evoltion of heat

Cmore solute molecules dissociate at hihger temperatures

Dmost solutes dissolve with absorption of heat

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