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Chemistry Past Questions

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82 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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82 questions

Question 1 of 20 82 total questions

Question 21

jamb 1993

Half-cell reaction. From the data above , it can be deduced that the most powerful reducing agent of the four metals is

ACu

BFe

CBa

DZn

View Explanation & Discuss

Question 22

jamb 1993

For which salt in the graph above does the solubility increase most rapidly with rise in temperature?

ACaSO₄

BKNO₃

CNaCl

DKCl

View Explanation & Discuss

Question 23

jamb 1993

Which of the curves above represents the behaviour of 1 mole of an ideal gas?

Bll

Clll

DlV

View Explanation & Discuss

Question 24

jamb 1993

A gas that will turn orange potassium heptaoxodichromate (lV) solution to clear green is?

Asulphur (ii) oxide

Bhydrogen sulphide

Csulphide (lV) oxide

Dhydrogen chloride

View Explanation & Discuss

Question 25

jamb 1993

The confirmatory test for alkanoic acids in organic qualitative analysis is the?

Aturning of wet blue litmus paper red

Breaction with alkanols to form esters

Creaction with sodium hydroxide to form salt and water

Dreaction with aqueous Na₂COsp₃ to liberate a gas which turns lime water milky

View Explanation & Discuss

Question 26

jamb 1993

Which of the following represents saponification?

AReaction of carboxylic acids with sodium hydroxide

BReaction of alkanoates with acid

CReaction of alkanoates with alcohols

DReaction of alkanoates with sodium hydroxide

View Explanation & Discuss

Question 27

jamb 1993

Catalytic hydrogenation of benzene produces?

Aan aromatic hydrocarbon

Bmargarine

Ccyclohexane

DD.D.T

View Explanation & Discuss

Question 28

jamb 1993

Palm wine turns sour with time because?

Athe sugar content is converted into alcohol

Bthe carbon (IV) oxide formed during the fermentation process has a sour taste

Cit is commonly adulterated by the tappers and sellers

Dmicrobial activity results in the production of orgain acids within it

View Explanation & Discuss

Question 29

jamb 1993

The carbon atoms on ethane are?

Asp² hybridized

Bsp³ hybridized

Csp²d hybridized

Dsp hybridized

View Explanation & Discuss

Question 30

jamb 1993

Al₂O_3(s) + 3H₂SO_4(aq) → Al₂(SO_4(aq)) + 3H_2(I)O
Al₂O_3(s) + 2NaOH_(aq)) + 3H_2(I)O → 2NaAl(OH)_4(aq)).
We can conclude from the equations above that Al₂O_3(s) is?

Aan acidic oxide

Ban amphoteric oxide

Ca basic oxide

Da neutral oxide

View Explanation & Discuss

Question 31

jamb 1993

It is not desirable to use lead tetraethyl as an anti-knock agent because?

Ait is expensive

Bof pollution effects from the exhaust fumes

Cit lowers the octane rating of petrol

Dit is explosive

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Question 32

jamb 1993

The fraction of crude oil used as jet fuel is?

Arefinery gas

Bdiesel oil

Ckerosene

Dgasoline

View Explanation & Discuss

Question 33

jamb 1993

The active reducing agent in the blast furnace for the extraction of iron is?

Acarbon

Blimestone

Ccarbon(II)oxide

Dcalcium oxide

View Explanation & Discuss

Question 34

jamb 1993

Bronze is an alloy of?

Asilver and copper

Bsilver and gold

Ccopper and nickle

Dcopper and zinc

Ecopper and tin

View Explanation & Discuss

Question 35

jamb 1993

When dilute aqueous solutions of lead (II) nitrate and potassium bromide are mixed, a precipitate is observed.
The products of this reaction are?

APbO_(s) + Br^- + KNO₃

BBr₂ + NO_2(g) + PbBr_2(s)

CPbO_(s) + K⁺_(aq) + Br_(aq) + NO_2(g)

DPbBr_2(s) + K_(aq) + K⁺_(aq) + NO_3(aq)

View Explanation & Discuss

Question 36

jamb 1993

Which of the following is a property of ionic chlorides?

AThey can be decomposed by heat

BThey react with aqueous AgNO₃ to give a white precipiate which is soluble in excess ammonia

CThey explode when in contact with dry ammonia

DThey react with concentrated tetraoxosulphate (IV) acid to give white fumes of chlorine gas

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Question 37

jamb 1993

An experiment produces a gaseous mixtures of carbon (IV) oxide and carbon (II) oxide. In order to obtain pure carbon (II) oxide, the gas mixture should be?

Apassed over heated copper (II) oxide

Bbubbled through concentrated tetraoxosulphate (IV) acid

Cbubbled through sodium hydroxide solution

Dbubbled through water

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Question 38

jamb 1993

Which of these salts will produce its metal, oxygen and nitrogen (IV) oxide on heating?

ASilver and trioxonitrate (V)

BSodium trioxonitrate (V)

CCalcium trioxonitrate (V)

DLithium trioxonitrate (V)

View Explanation & Discuss

Question 39

jamb 1993

Which of these gases can be dried with concentrated H2SO4?

AHBr

BH₂S

CNH₃

DSO₂

View Explanation & Discuss

Question 40

jamb 1993

NaCI_(s) + H₂SO_4(I) → HCI_(g) + NaHSO_4(s).
In the reaction above, H₂SO₄ behaves as?

Aa strong acid

Ban oxidizing agent

Ca good solvent

Da dehydrating agent

View Explanation & Discuss

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