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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.

168 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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168 questions

Question 1 of 20 168 total questions

Question 11

neco 2009

How many zones are present in a luminous Bunsen burner flame?

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Question 12

neco 2009

When air is passed through alkaline pyrogallol and then lime water, the gases left are

Anitrogen and carbon (IV) oxide

Bnitrogen and noble gases

Cnitrogen and oxygen

Dnitrogen, carbon (VI) oxide and noble gases

Ethe noble gases

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Question 13

neco 2009

A salt which loses its mass when exposed to air is

Adeliquescent

Beffervescent

CEfflorescent

Dfluorescent

Ehygroscopic

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Question 14

neco 2009

Atomic size decreases

Aacross a period from left to right

Bacross a period from right to left

Cdiagonally down the group

Ddown a group

Ewith decrease in atomic number

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Question 15

neco 2009

Sulphur has an oxidation number of +4 in

AH₂S

BH₂S0₄

CMgSO₄

DNa₂SO₃

ES0₃

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Question 16

neco 2009

If the volume of a gas at 35°C is 60cm\(^3\), what would be its volume in cm\(^3\) at 273k?

A39.03

B46.81

C53.18

D67.69

E76.92

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Question 17

neco 2009

C\(_6\)H\(_{12}\)O\(_6\)

What is the molar mass of the compound above?

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

A45

B61

C180

D123

E244

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Question 18

neco 2009

In the electrolysis of dilute tetraoxosulphate (VI) acid using platinum electrodes, the products obtained at the anode are cathode respectively are

Ahydrogen, oxygen

BHydrogen, tetraoxosulphate (VI) ion

Coxygen, hydrogen

Dsulphur, hydrogen

Esulphur, oxygen

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Question 19

neco 2009

A neon atom is chemically nonreactive because

Athe electrons at the outermost shell is partially filled

Bthe number of protons equals the number of electrons

Cthe outer electron shell is completely filled

Dthere are equal number of protons and neutrons in its nucleus

Ethere are no elections at the outermost shell

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Question 20

neco 2009

\( ^{235}_{92}U + ^1_0n → ^{145}_{56}Ba + ^{88}_{36}Kr + 3^1_0n + Energy \)

The equation above represent a/an

Aalpha particle emission

Bendothermic reaction

Cnuclear fission

Dnuclear fusion

Ethermal dissociation

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Question 21

neco 2009

Which of these compounds has the greatest ionic character?

AAlF₃

BBF₂

CCF₄

DCsF

ENaF

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Question 22

neco 2009

What kind of bond exist between carbon and oxygen in C0₃ ^2-?

ACo- ordinate Covalent

Bcovalent

CElectrovalent

DMetallic

EVan der Waal forces

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Question 23

neco 2009

Which of the following gases will bleach moist litmus paper?

ACl₂

BCO₂

CHCl

DN₂O

ESO₃

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Question 24

neco 2009

Which of the following compounds will undergo thermal dissociation?

AAgCl

BCaCO₃

CK₂S0₄

DNaOH

ENH₄CI

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Question 25

neco 2009

The rate of a reaction usually increases with increase in the concentration of reactants because the

Adistance between particles of the reactants increases

Bfrequency of collision of particles is lower

Cparticles of the reactants gain energy and move faster

Dreactants from a complex which decomposes rapidly

Ereactants occupy a higher energy level

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Question 26

neco 2009

The reaction of an alkanol with alkanioc acid is known as

Adehydration

Besterification

Chalogenation

Dhydrogenation

Esaponification

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Question 27

neco 2009

The empirical formula of a hydrocarbon containing 0.12 mole of carbon 0.3 mole of hydrogen is

ACH₂

BCH₃

CC₂H₂

DC₂H₄

EC₂H₆

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Question 28

neco 2009

Which of the following statements is NOT correct of group VII elements? They

Aare diatomic

Bare good oxidizing agents

Care highly electronegative

Dhave high electron affinity

Ehave relatively low ionization potentials

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Question 29

neco 2009

Which of the following is NOT a fraction of petroleum?

ABitumen

BCoal

CDiesel

DKerosene

EPetrol

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Question 30

neco 2009

The scientist who discovered the zig-zag movement of gas molecules is

ABrownian

BDalton

CGay Lussac

DGraham

ENewton

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