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Chemistry Past Questions

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45 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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Past Questions

45 questions

Question 1 of 20 45 total questions

Question 11

jamb 1984

Alkaline hydrolysis of naturally occurring fats and oils yields

Afats and acids

Bsoaps and glycerol

Cmargarine and butter

Desters

Edetergents

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Question 12

jamb 1984

When the kerosene fraction from petrol is heated at high temperature, a lower boiling liquid is obtained. This process is known as

Apolymerization

Brefining

Chydrogenation

Dcracking

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Question 13

jamb 1984

An organic compound with a vapour density 56.5 has the following percentage composition:C =53.1% N = 12.4%, O = 28.3%, H = 6.2%. The molecular formula of the compound is
Relative atomic masses: N = 14, O = 16, C = 12, H = 1 )

AC₃H₆O₂N

BC₅H₆O₂N

C(C₅H₇O₂N)_1/2

DC₅H₇O₂N

E(C₅H₇O₂N)₂

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Question 14

jamb 1984

The hybridization of the carbon atom in ethyne is

Asp ⁴

Bsp ³

Csp²

Dsp

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Question 15

jamb 1984

In the Haber process for the manufacture of ammonia, finely divided iron is used as

Aan ionizing agent

Ba reducing agent

Ca catalyst

Da dehydrating agent

Ean oxidizing agent

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Question 16

jamb 1984

3Cl₂ + 2NH₃ \(\to\) N₂ + 6HCl. In the above reaction, ammonia acts as

Aa reducing agent

Ban oxidizing agent

Can acid

Da catalyst

Ea dry agent

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Question 17

jamb 1984

An example of a neutral oxide is

AAL₂O₃

BNO₂

CCO₂

DCO

ESO₂

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Question 18

jamb 1984

From the reactions : ZnO + Na₂O \(\to\) NaZnO and ZnO + CO₂ \(\to\) ZnCO₃ it may be concluded that zinc oxide is

Aneutral

Bbasic

Cacidic

Damphoteric

Ea mixture

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Question 19

jamb 1984

Which of the following statements is NOT true of carbon monoxide?

ACO is poisonous

BCO is readily oxidized at room temperature by air to form CO₂

CCO may be prepared by reducing CO₂ mixed with coke heated to about 1000^oC

DCO may be prepared by heating charcoal with a limited amount of O₂

ECO is a good reducing agent

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Question 20

jamb 1984

Sulphur

Aforms two alkaline oxides

Bis spontaneously flammable

Cburns with a blue flame

Dconducts electricity in the molten state

Eis usually stored in the form of sicks in water

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Question 21

jamb 1984

An element that can exist in two or more different structural forms which possess the same chemical properties is said to exhibit.

Apolymerism

Bisotopy

Cisomorphism

Disomerism

Eallotrophy

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Question 22

jamb 1984

Lime - water, which is used in the laboratory for the detection of carbon(iv)oxide is an aqueous solution of

ACa(OH)₂

BCaCO₃

CCaHCO₃

DCaSO₄

EN₂CO₃

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Question 23

jamb 1984

Which of the following methods may be used to prepare trioxonitrate (V) acid (nitric acid) in the laboratory?

AHeating ammonia gas with tetraoxosulphate (VI) acid

BHeating ammonium trioxonitrate (V) with tetraoxosulphate (VI) acid

CHeating sodium trioxonitrate (V) with tetraoxosulphate (VI) acid

DHeating potassium trioxonitrate (V) with calcium hydroxide

EHeating a mixture of ammonia gas and oxygen.

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Question 24

jamb 1984

In dilute solution the heat of the reaction NaOH + HCl = NaCl + H2O is - 57.3kJ. Therefore the heat of the reaction 2NaOH + H₂SO₄ \(\to\) Na₂SO₄ + 2H₂O is

A+ 28.65 kJ

B- 28.65KJ

C+ 57.3KJ

D- 114.6 KJ

E- 229.2 KJ

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Question 25

jamb 1984

For the reaction 2Fe³⁺ 2I^- \(\to\) 2Fe²⁺ + I₂, which of the following statements is TRUE?

AFe is oxidized to Fe³⁺

BFe³⁺ is oxidized to Fe²⁺

CI^- is oxidized to I₂

DI^- is reduced to I₂

EI^- is displacing an electron from Fe³⁺

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Question 26

jamb 1984

In which of the following reactions does hydrogen peroxide act as a reducing agent?

AH₂S + H₂O₂ \(\to\) S + 2H₂O

BPbSO₃ + H₂O₂ \(\to\) PbSO₄ + H₂O

C2I+ 2H⁺ + H₂O₂ \(\to\) I₂ + 2H₂O

DPbO₂ + 2HNO₃ + H₂O₂ \(\to\) Pb(NO₃)₂ + 2H₂O + O₂

ESO₂ + H₂O₂ \(\to\) H₂SO₄

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Question 27

jamb 1984

Which of the following mixtures would result in a solution of pH greater than 7?

A25.00 cm³ of 0.05 M H₂SO₄ and 25.00cm³ of 0.50 M Na₂CO₃

B25.00 cm³ of 0.05 M H₂SO₄ and 25.00 cm³ of 0.10 M NaHCO₃

C25.00 cm³ of 0.11 MH₂SO₄ and 25.00cm³ 0. 10 M NaOH

D25.00cm³ of 0.11 MH₂ SO₄ and 50.00 cm³ of 0.05 M NaOH

E25.00cm³ of 0.25 M H₂SO₄ and 50.00cm³ of 0.20 M NaOH

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Question 28

jamb 1984

The balanced equation for the reaction of tetraoxosulphate(VI)acid with aluminium hydroxide to give water and aluminium tetraoxosulphate(VI) is

AH₂SO₄ + Al(OH)₂ \(\to\) 2H₂O + AlSO₄

B3H₂SO₄ + 2Al(OH)₃ \(\to\) 6H₂O + Al₂(SO₄)₃

C3H₂SO₄ + 2AlH \(\to\) 6H₂O + Al(SO₄)₃

D3H₂ SO₄ + 2Al(OH)₃ \(\to\) Al(SO₄)₃

EH₂SO₄ + Al(OH)₃ \(\to\) H₂O + Al₂(SO₄)₃

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Question 29

jamb 1984

The ratio of the number of molecules in 2g of hydrogen to that in 16g of oxygen is

A2:1

B1:1

C1:2

D1:4

E1:8

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Question 30

jamb 1984

Naphthalene when heated melts at 354 K (81 ^oC). At this temperature the molecules of naphthalene

Adecompose into smaller molecules

Bchange their shape

Care oxidized by atmospheric oxygen

Dcontract

Ebecome mobile as the inter molecular forces are broken

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