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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.

52 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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Past Questions

52 questions

Question 1 of 20 52 total questions

Question 1

waec 2002

One of the methods used for combating air pollution is

Aburning of solid waste

Bprovision of sanitary land fills

Clegislation against some industrial practices

Dscavenging of refuse dumps

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Question 2

waec 2002

Iron is often galvanized in order to

Amake it more malleable

Bremove the impurities in it

Cprotect it against corrosion

Drender it passive

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Question 3

waec 2002

The energy value of petrol can be determined by a

Abomb calorimeter

Bcatalytic cracker

Cfractionating column

Dthermometer

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Question 4

waec 2002

The reaction of sucrose with dilute HCI produces

Aan alkanoate

Bglucose and fructose

Ca black mass of carbon

Da polysaccharide

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Question 5

waec 2002

A suitable reagent for distinguishing between ethanoic acid ethanol is

Abromine water

BFehling's solution

Csodium hydrogentrioxocarbonate (IV)

Dammoniacal silver trioxonitrate (V)

View Explanation & Discuss

Question 6

waec 2002

Which of the following types of alkanols undergo oxidation to produce alkanoic acids? I. Primary alkanols II. Secondary alkanols III. Tertiary alkanols

AI,II and III

Bl and ll only

Cll only

Dl only

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Question 7

waec 2002

Which of the following statements about soapless detergents is correct? They

Alather readily with hard water

Bincrease the surface tension of water

Ccause hydrolysis of salts in water

Dfrom a curdy precipitate with soft water

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Question 8

waec 2002

The reaction between ethene and chlorine to form 1, 2-dichloroethane is

Aoxidation

Bpolymerization

Caddition

Dsubstitution

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Question 9

waec 2002

The following compounds are hydrocarbons except

Amethylpropanoate

B2-methylbutane

Cbenzene

Dcyclohexane

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Question 10

waec 2002

When alkynes are hydrogenated completely they produce compounds with the general molecular formula

AC_nH_n

BC_nH_2n

CC_nH_2n+2

DC_nH_2n-2

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Question 11

waec 2002

Which of the following compounds can be represented by the molecular formula C₂H₆O?

APropanal

BEthanol

CMethanoic acid

DGlucose

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Question 12

waec 2002

Which of the following processes takes place during the production of margarine from vegetable oils?

AEsterification

BHydrolysis

CHydrogenation

DSaponification

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Question 13

waec 2002

When concentrated sodium chloride solution is electrolysed using inert electrodes, the products are

Aoxygen and hydrogen

Bhydrogen and chlorine

Csodium and oxygen

Dsodium and chlorine

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Question 14

waec 2002

If two metallic ions of the same concentration migrate to a graphite cathode, the one that would be preferentially discharged is the one that has the

Asmaller mass

Blower electrical charge

Cgreater stability in solution

Dstronger tendency to accept electrons

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Question 15

waec 2002

Which of the following ions require the largest quantity of electricity for discharge at an electrode?

A2.0 mole of Q ³⁺

B2.5 mole of R²⁺

C3.0 mole of T^-

D4.0 mole of Y^-

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Question 16

waec 2002

Consider the following equation: Cr\(_2\)O\(_7\)\(^{2-}\)(aq) + 14H\(^+\)(aq) + 6e\(^-\) → 2Cr\(^{3+}\)(ag) + 7H\(_2\)O(1). The oxidation number of chromium changes from

A-2 to + 3

B-2 to + 6

C+6 to +3

D+7 to + 6

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Question 17

waec 2002

A visible change is observed when a strip of iron is placed in an aqueous solution of

AFeSO₄

BZnSO₄

CCuSO₄

DMgSO₄

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Question 18

waec 2002

Which of the following compounds will leave a metal residue when heated?

ACu(NO₃)₂

BAgNO₃

CK₂CO₃

DCaCO₃

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Question 19

waec 2002

CuSO₄5H₂O can be obtained from an aqueous solution of copper (ll) tetraoxosulphate (VI) by

Aevaporation to dryness

Busing chromatography

Cprecipitation

Dcrystallization

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Question 20

waec 2002

Equal amounts of marble chips are reacted separately with 100cm3 of hydrochloric acid of different concentrations. If all the marble chips reacted; which of the following remained the same in each case?

AAverage rate of evoluton of gas

BTotal mass of gas evolved during the reaction

CTime taken for the reaction to reach completion

DInitial reaction rates

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