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Chemistry Past Questions

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4,306 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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4,306 questions

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Question 791

jamb 2012

The isomers of C₃H₈O ARE

A1 - propanol and 2 - propanol

B1 - propanol and 1 - propanol

C2 - propanol and 2 - propanone

D2 - propanol and 1 - propanol

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Question 792

jamb 2012

Alkanals can be distinguished from alkanones by the reaction with

Asudan lll stain

Bstarch iodide paper

Clithium tetrahydrido aluminate (lll)

Dfehling's solution

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Question 793

jamb 2012

Geometric isomerism can exist in

Ahex-3-ene

Bhexane

Cprop-l-ene

D3-methyl but -l-ene

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Question 794

jamb 2012

Which of the following metals is the least reactive?

APb

BSn

CHg

DAu

View Explanation & Discuss

Question 795

jamb 2012

A common characteristic between zinc and the other transition elements is the ability to

Ahave variable oxidation states

Bfrom complex ions

Cact as a catalyst

Dfrom coloured ions

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Question 796

jamb 2012

The purest form of iron which contains only about 0.1% carbon is

Apig iron

Bwrought iron

Ccast iron

Diron pyrite

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Question 797

jamb 2012

Which of the following compounds will burn with a brick-red colour in a non-luminous Bunsen flame?

ALiCI

BNaCl

CCaCl₂

DMgCl₂

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Question 798

jamb 2012

Mineral acids are usually added to commercial hydrogen peroxide to

Aoxidize it

Bdecompose it

Cminimize its decomposition

Dreduce it to water and oxygen

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Question 799

jamb 2012

Commercial bleaching can be carried out using

Asulphur (IV) oxide and ammonia

Bhydrogen sulphide and chlorine

Cchlorine and sulphur (IV) oxide

Dammonia and chlorine

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Question 800

jamb 2012

Which of the following gases has a characteristic pungent smell, turns red litmus paper blue and forms dense white fumes with hydrogen chloride gas?

AN₂

BN₂O

CCI₂

DNH₃

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Question 801

jamb 2012

A piece of filter paper moistened with lead (ll) ethanoate solution turns black when the paper is dropped into a gas likely to be

Asulphur (VI) oxide

Bhydrogen chloride

Csulphur (VI) oxide

Dhydrogen sulphide

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Question 802

jamb 2012

The highest rate of production of carbon (lV) oxide can be achieved using

A0.05 mol ^-3HCI and 5g powdered CaCO₃

B0.05 mol ^-3HCI and 5g lump CaCO₃

C0.10 mol ^-3HCI and 5g powdered CaCO₃

D0.025 mol ^-3HCI and 5g powdered CaCO₃

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Question 803

jamb 2012

An increase in entropy can best be illustrated by

Amixing of gases

Bfreezing of water

Cthe condensation of vapour

Dsolidifying candle wax

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Question 804

jamb 2012

CO(g) + H\(_2\) O\(_{(g)}\) → CO\(_{2(g)}\) + H\(_{2(g)}\)
Calculate the standard heat change of the reaction above, if the standard enthalpies of formation of CO\(_{2(g)}\), H\(_2\)O\(_{(g)}\) and CO\(_{(g)}\) in kJmol\(^{-1}\) are - 394, -242 and - 110 respectively.

A+ 262 KJ mol ^-1

B- 262 KJ mol ^-1

C+ 42 KJ mol ^-1

D- 42 KJ mol ^-1

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Question 805

jamb 2012

A metal M displaces zinc from ZnCl solution
This shows that

Aelectrons flow from zinc to M

BM is more electropositive than zinc

CM is more electonegative than zinc

Dzinc is more electropositive than M

View Explanation & Discuss

Question 806

jamb 2012

What number of moles of Cu 2+ will be deposited by 360 coulombs of electricity?
[f = 96500 C mol -1]

A5.36 x 10 ^-4 mole

B1. 87 x 10 10 ^-3 mole

C9. 35 x 10 ^-4 mole

D3. 73 x 10 ^-3

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Question 807

jamb 2012

2\(Na_2O_{2(s)} + 2H_2O_{(1)}\)→ 4\(NaOH_{(s)} +O_{2(g)}\)
The substance that is oxidized in the reaction above is

A\(Na_2O_{2(s)}\)

BNaOH(aq)

CH₂O₍₁₎

DO_2(g)

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Question 808

jamb 2012

The oxidation number of boron in NaBH ₄ is

A-3

B-1

C+1

D+3

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Question 809

jamb 2012

A major factor considered in selecting a suitable method for preparing a simple salt is its

ACrystalline from

Bmelting point

Creactivity with dilute acids

Dsolubility in water

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Question 810

jamb 2012

During a titration experiment, 0.05 moles of carbon (lV) oxide is liberated. What is the volume of gas liberated?

A22.40 dm ³

B11.20 dm ³

C2.24 dm ³

D1.12 dm ³

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