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Chemistry Past Questions

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2,505 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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2,505 questions

Question 1 of 20 2,505 total questions

Question 1011

jamb 1988

Aluminium is extracted commercially from its ore by?

Aheating aluminium oxide with coke in a furance

Bthe electrolysis of fused aluminium oxide in cryolite

Ctreating cryolite with sodium hydroxide solution under prressure

Dheating sodium aluminium silicate to a high temperature

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Question 1012

jamb 1988

Chlorine is produced commmercially by?

Aelectrolysis of dilute hydrochloric acid

Belectrolysis of brine

Cneutralization of hydrogen chloride

Dheating potassium trioxochlorate (V)

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Question 1013

jamb 1988

The thermal decomposition of copper (ll)trioxonitrate (V) yields copper (ll) oxide, oxygen and?

Anitrogen (ll) oxide

Bnitrogen (l) oxide

Cnitrogen (lV) oxide

Dnitrogen

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Question 1014

jamb 1988

Suitable reagents for the laboratory preparation nitrogen are?

Asodium dioxonitrate (III) and ammonium chloride

Bsodium dioxonitrate (V) and ammonium chloride

Csodium chloride and ammonium chloride

Dsodium chloride and ammonium diozonitrate (III)

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Question 1015

jamb 1988

When H₂S gas is passed into a solution of iron (III) chloride, the colour changes from yellow to green. This is because?

AH_(s)S is reduced to S

BFe³⁺ ions are oxidized by H_(s)S

CFe³⁺ ions are oxidized Fe³⁺ ions

DFe³⁺ ions are reduced to Fe²⁺ ions

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Question 1016

jamb 1988

Which of the following is used in fire extinguishers?

ACarbon (ll) oxide

BCarbon (lV) oxide

CSulphur (lV) oxide

DAmmonia

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Question 1017

jamb 1988

Which property of a reversible reaction is affected by a catalyst?

AHeat content (enthalphy)

BEnergy of activation

CFree energy change

DEquilibrium position

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Question 1018

jamb 1988

Which of the followingstatements is TRUE?

AThe dissolution of NaOH_(s) in water is endothermic

BThe heat os solution of NaOH_(s) is positive

CThe NaOH_(s) gains heat from the surroundings

DThe heat of solution of NaOH_(s) is negative

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Question 1019

jamb 1988

Which of the following will produce the greatest increase in the rate of the chemical reaction represented by the equation Na2S2O3(aq) + 2HCl(aq) → 2NaCI(aq) + H2O(I) + SO2(g) + S(g)?

AA decrease in temperature and an increase in the concentration of the reactants

BAn increase in the temperature and a decrease in the cocentration of the reactants

CAn increase in temperature and an increase in the concentration of the reactants

DA decrease in the temperature and a decrease in the concentration of the reactants

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Question 1020

jamb 1988

A mixture of starch solution and potassium iodide was placed in a test tube. On adding dilute tetraoxosulphate (lV) acid and then K₂Cr₂O₇ solutions, a blue-black colour was produced. In this reaction, the?

Aiodide is oxidized

Btetraoxosulphate (Vl) acid acts as an oxidizing agent

Cstarch has been oxidized

DK₂Cr₂O₇ is oxidized

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Question 1021

jamb 1988

Which of the following reactions takes place in the cathode compartment during the electrolysis of copper (II) chloride solution?

ACu²⁺ + 2e^- → Cu(s)

B2Cl^- -2e → Cl₂

CCu_(s) -2e → Cu²⁺_(aq)

DCu²⁺_(aq) + 2Cl^-_(aq) → CuCl_2(aq)

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Question 1022

jamb 1988

Which of the following acts both s a reducing and an oxidizing agent?

AH₂

BSO₂

CH₂S

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Question 1023

jamb 1988

Which of the following substances is a basic salt?

ANa₂CO₃

BMg(OH)CI

CNaHCO₃

DKSO₄.AI₂(SO₄)₃,24H₂O

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Question 1024

jamb 1988

What volume of a 0.1 M H\(_3\)PO\(_4\) will be required to neutralize 45.0 cm\(^3\) of a 0.2 M NaOH?

A10.0 cm³

B20.0 cm³

C27.0 cm³

D30.0 cm³

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Question 1025

jamb 1988

Which of the following in aqueous solution is neutral to litmus?

ANH₄CI

BNaCO₃

CFeCl₃

DNaCl

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Question 1026

jamb 1988

Which of the following dilute solutions has the lowest pH value?

ACalcium trioxocarbonate (IV)

BSodium trioxocarbonate (IV)

CHydrochloric acid

DEthanoic acid

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Question 1027

jamb 1988

A substance S is isomorphous with another substance R. When a tiny crystals of S is added into a supersaturated solution of R?

AS dissolves in the solution

Bcrystals of R are precipitated

Cthere is no observable change

DR and S react to generate heat

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Question 1028

jamb 1988

The ion that may be assumed to have negligible concentration in a sample of water that lathers readily with soap is?

AMg⁺

BK⁺

CCO₂^2-

DHCO₃

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Question 1029

jamb 1988

Which of the following statements is NOT correct?

AThe average kinetic energy of a gas is directly proportional to its temperature

BAt constant temperature, the volume of a gas increases as the pressure increases

CThe pressure of a gas is directly proportional to the density.

DThe temperature of a gas is directly proportional to its volume

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Question 1030

jamb 1987

Use the option above to answer this question. The structure of benzoic acid is

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