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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.

93 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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Past Questions

93 questions

Question 1 of 20 93 total questions

Question 1

waec 2011

Aluminium is extracted electrolysis from

Abauxite

Bcryolite

Cduralumin

Dkaolin

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Question 2

waec 2011

Which of the following processes does not involve the use of limestone?

AExtraction of iron in the blast furnance

BManufacture of tetraoxosulphate (VI) acid by Contact process

CProduction of washing soda by Solvay process

DProduction of cement

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Question 3

waec 2011

The following substances are ores of metals except

Abauxite

Bcuprite

Ccassiterite

Dgraphite

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Question 4

waec 2011

The reagent that can be used to distinguish ethene from ethyne is

Aammoniacal silver trioxonitrate (V) solution

BBenedict solution

Cbromine water

DFehling's solution

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Question 5

waec 2011

The compound that makes palm wine taste sour after exposure to the air for few days is

Aethanol

Bethanoic acid

Cmethanol

Dmethanoic acid

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Question 6

waec 2011

When bromine is added to ethene at room temperature, the compound formed is

A1,1 - dibromoethane

B1,2 - dibromoethene

C1,1 - dibromoethene

D1,2 - dibromoethane

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Question 7

waec 2011

The following substances are examples of addition polymer except

Anylon

Bperspex

Cpolyethene

Dpolychloroethene

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Question 8

waec 2011

Which of the following separation techniques would show that black ink is a mixture of chemical compounds?

ACrystallization

BChromatography

CFiltration

DSublimation

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Question 9

waec 2011

Which of the following compounds would react with ethanoic acid to give a sweet smelling liquid?

AAlkane

BAlkanol

CAlkanal

DAlkyne

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Question 10

waec 2011

Which of the following compounds determines the octane rating of petrol?

A1,2,3 - trimethlpentane

B2,3,5 - trimethyloctane

C2,3,5 - trimethylpentane

D2,2,4 - trimethylpentane

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Question 11

waec 2011

Consider the following electrochemical cell notation: M(s) / M2+ (aq)// H+ (aq)/ H2(g). The value of the electrode potential is positive when?

Aelectrons flow from the metal electrode, M_(s) to hydrogen electrode, H_2(g)

Belectrons fow from hydrogen electrode, H_2(g) to metal electrode, M_(s)

Cthe flow of current is high

Dthere is equilibrium between the flow of electrons from the hydrogen electrode, H_2(g) to metal electrode, M_(s)

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Question 12

waec 2011

Which of the following metals could be used as sacrifical anode for preventing the corrosion of iron?

ACopper

BLead

CMagnesium

DSilver

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Question 13

waec 2011

What mass of copper would be formed when a current of 10.0 A is passed through a solution of CuSO₄ for 1 hour? [Cu = 63.5; 1F = 96500C]

A5.9 g

B11.8 g

C23.8 g

D47.3 g

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Question 14

waec 2011

What is the value of n in the following equation? Cr₂O₇^2- + 14H⁺ + ne^- → 2Cr ³⁺ + 7H₂O

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Question 15

waec 2011

Consider the following reaction equation:

X(g) + Y(g) ⇌ XY(g); ∆H = + 220KJ mol-1 If the temperature of the system is increased, the

Abackward reaction would be favoured

Bforward reaction would favoured

Creaction would stop

Dreaction would be at equilibrium

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Question 16

waec 2011

On evaporation to dryness, 250 cm3 of saturated solution of salt X with relative molar mass 101 gave 50.5g of the. What is the soluility of the salt?

A1.0 mol dm^-3

B2.0 mol dm^-3

C4.0 moldm^-3

D5.0 moldm^-3

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Question 17

waec 2011

Which of the following metallic oxides is amphoteric?

AAI₂O₃

BFe₂O₃

CMgO

DNa₂O

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Question 18

waec 2011

When NH ₄CI was dissolved in water, the container was cold to touch. This implies that

Athe process is endothermic

Bthe process is exothermic

CNH₄CI is highly soluble in water

DNH ₄CI forms a saturated solution

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Question 19

waec 2011

Which of the following statements about enthalpy of neutralization is correct? It

Ais constant for a strong acid and a strong base

Bcannot be determined using calorimeter

Chas a positive value

Dis higher for strong acid and a weak base

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Question 20

waec 2011

The colour of phenolphthalein indicator in alkaline solution at the end-point of an acid-base titration is?

Acolourless

Borange

Cpink

Dyellow

View Explanation & Discuss

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