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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

Question 1 of 20 4,306 total questions

Question 1941

jamb 1986

In the electrolysis of aqueous solution of K₂SO ₄ in the above cell, which species migrate to the anode?

ASO^2-OH ^-

BK ⁺ and SO ₄ ^2-

COH and HO

DH₃O ⁺ and K

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Question 1942

jamb 1986

In the solubility curve above, water at 98\(^0\)C is saturated with KCl and KCIO\(_3\). What is the percentage of KCl impurity in the crystals formed when the solution is cooled to 30\(^0\)C?

A51.5

B45.5

C34.5

D26.5

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Question 1943

jamb 1986

What mass of a divalent metal M (atomic mass = 40) would react with excess hydrochloric acid to liberate 224cm^3 dry hydrogen gas measured at S.T.P?

A8.0 g

B4.0 g

C0.8 g

D0.4 g

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Question 1944

jamb 1986

The movement of liquid molecules from the surface of the liquid to the gaseous phase above it is known as?

ABrownian movement

Bcondensation

Cevaporation

Dliquefaction

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Question 1945

jamb 1986

Starch can be converted to ethyl alcohol by?

Adistillation

Bfermentation

Cisomerization

Dcracking

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Question 1946

jamb 1986

Which of the following are made by the process of polymerization?

ANylon and soap

BNylon and artificial rubber

CSoap and butane

DMargarine and nylon

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Question 1947

jamb 1986

The general formula of an alkyl halide (where X represents the halide) is?

AC_nH_2n ₂X

BC_nH_2n + ₁X

CC_nH_2n + ₂X

DC_nH_2nX

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Question 1948

jamb 1986

Which of the following substance is a mixture?

AGranulated sugar

BSea-water

CSodium chloride

DIron fillings

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Question 1949

jamb 1986

Which of the following compounds is NOT formed by the action of chlorine on methane?

ACH₃CI

BC₂H₅CI

CCH₂CI₂

DCHCI₃

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Question 1950

jamb 1986

When ethanol is heated with excess concentrated sulphuric acid, the ethanol is?

Aoxidized to ethene

Bpolymerized to polyethene

Cdehydrated to ethene

Ddehydrated to ethyne

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Question 1951

jamb 1986

What reaction takes place when palm-oil is added to potash and foam are observed?

ANeutralization

BSaponification

CEsterification

DSalting-out

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Question 1952

jamb 1986

Which of the following is used as an 'anti-knock' in automobile engines?

ATetramethyl silane

BLead tetra-ethyl

CGlycerol

Dn-heptane

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Question 1953

jamb 1986

Which of the following is NOT correct test for the named organic compound in each case?

AButanoic acid solution gives effervescence with Na₂CO₃ solution

BGlucose when reacted with Na₂CrO₄ at 0°C will show immediate discharge of colour

CWhen but-2-ene is reacted with dilute solution of KMnO₄ the purple colour of KMnO is discharged readily even room temperature

DWhen butan-2-ol is boiled with butanoic acid with a drop of concentrated H₂SO₄ a sweet smelling liquid is produced

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Question 1954

jamb 1986

How will a metal X, which reacts explosively with air and with dilute acids be best extracted from its ores?

AElectrolysis of solution of its salts

BDecomposition of its oxides

CDisplacement from solution by an alkali metal

DElectroiysis of fused salt

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Question 1955

jamb 1986

Which of the following compounds would give lilac flame coloration and a white precipitate with acidified barium chloride solution?

AKCI

BNaNO₃

CK₂SO₄

DCaSO₄

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Question 1956

jamb 1986

A white solid suspected to be lead trioxonitrate (V) zinc trioxocarbonate (IV) or calcium trioxocabonate (IV) was heated strongly. Its residue which was yellow when hot and white when cold is?

Alead (II) oxide

Bcalcium oxide

Czinc oxide

Dlead nitrate

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Question 1957

jamb 1986

Which of the following does NOT contain aluminium as component?

AOver-head cables

BDuralumin

CContainer for caustic soda

DContainer for nitric acid

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Question 1958

jamb 1986

The iron (III) oxide impurity in bauxite can be removed by?

AFractional crystallization in acid solution

Bdissolution in sodium hydroxide and filtration

Cextraction with concentrated ammonia and reprecipitation

Delectroysis of molten mixture

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Question 1959

jamb 1986

What are the values of x, y and z respectively in the equation: xCu + yHNO₃ → xCu(NO₃)₂ + 4H₂O + zNO?

A4: 1: 2

B3:8:2

C2:8:3

D8:3:2

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Question 1960

jamb 1986

Ammonia gas is normally dried with?

Aconcentrated sulphuric acid

Bquicklime

Canhydrous calcium chloride

Dmagnesium sulphate

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