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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 831

jamb 1995

The role of sodium chloride in the preparation of soap is to?

Apurify the soap

Bseparate the soap from glycerol

Caccelerate the decomposition of the fat or oil

Dreact with glycerol

View Explanation & Discuss

Question 832

jamb 1995

Aromatic and aliphatic hydrocarbons can be distinguished from each other by the?

Aaction of bromine

Buse of polymerization reaction

Caction of heat

Duse of oxidation reaction

View Explanation & Discuss

Question 833

jamb 1995

Which of the following pairs has compounds that are isomers?

APropanal and propanone

BEthanoic acid and ethylmethanoate

CEthanoic acid and ethane-1, 2-diol

D2-methylbutane and 2, 2-dimethylbutane

View Explanation & Discuss

Question 834

jamb 1995

CHCl₃ + Cl₂ → HCl + CCl₄. The reaction above is an example of?

Aan addition reaction

Ba substitution reaction

Ca chlorination reaction

Da condensation reaction

View Explanation & Discuss

Question 835

jamb 1995

Group 1 A metals are not found free in nature because they?

Aare of low melting and boiling points

Bhave weak metallic bonding

Cconduct electricity and heat

Dare very reactive

View Explanation & Discuss

Question 836

jamb 1995

Which of the following compounds will impart a brick-red colour to a non-luminious bunsen flame?

ANaCl

BLiCl

CCaCl₂

DMgCl₂

View Explanation & Discuss

Question 837

jamb 1995

In the extraction of iron in the blast furnace, limestone is used to?

Arelease CO₂ for the reaction

Breduce the iron ore

Cincrease the strenght of the iron

Dremove impurities

View Explanation & Discuss

Question 838

jamb 1995

Which of the following ions will give a white precipitate with aqueous NaOH and soluble in excess of the base?

ACa²⁺

BMg²⁺

CZn²⁺

DCu²⁺

View Explanation & Discuss

Question 839

jamb 1995

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

Asulphur (lV) oxide

Bhydrogen sulphide

Csulphide (lV) oxide

Dhydrogen chloride

View Explanation & Discuss

Question 840

jamb 1995

Sulphur exists in six forms in the solid state. This property is known as?

Aisomerism

Ballotropy

Cisotopy

Disomorphism

View Explanation & Discuss

Question 841

jamb 1995

In the industrial production of hydrogen from natural gas, carbon (IV) oxide produced along with the hydrogen is removed by?

Awashing with water under pressure

Bpassing the mixture into lime water

Cusing ammoniacal copper (l) chloride

Ddrying over phoshorus (V) oxide

View Explanation & Discuss

Question 842

jamb 1995

Which of the following equilibria is shifted to the right as a result of an increase in pressure?

AH_2(g) + I_2(g) 2HI_(g)

B2NO_2(g) N₂O_4(g)

CPCl_5(s) PCl_3(s) + Cl_2(g)

D2O_3(g) 3O_2(g)

View Explanation & Discuss

Question 843

jamb 1995

Which of the following processes leads to increase in entropy?

AMixing a sample of NaCl and sand

BCondensation of water vapour

CBoiling a sample of water

DCooling a saturated solution

View Explanation & Discuss

Question 844

jamb 1995

If an equilibrium reaction has ∆H < O, the reaction will proceed favorably in the forward reaction at?

Alow temperatures

Bhigh temperatures

Call temperatures

Dall pressures

View Explanation & Discuss

Question 845

jamb 1995

Cr\(_2\)O\(_7\)\(^{2-}\)(aq) + 14H\(^+\)(aq) + 6l\(^-\)(aq) → 2Cr\(^{3+}\)(aq) + 3l(g) + 7H\(_2\)O(I).
The change in the oxidation number of oxygen in the equation above is?

View Explanation & Discuss

Question 846

jamb 1995

Which of the following is a redox reaction?

AKCI_(aq) + H₂SO_4(aq) → KHSO_4(aq) + HCI_(aq)

B2FeBr_2(aq) + Br_4(aq) → 2FeBr_3(aq)

C3AgNO_(aq) + FeCl_3(aq) → 3AgCl_(aq) + Fe(NO₃)_3(aq)

DH₂CO_3(aq) → H₂O_(I)2- + CO_2(g)

View Explanation & Discuss

Question 847

jamb 1995

2CL^-_(aq) → CI_2(g) + 2e^-(aq). The above half-cell reaction occuring at the anode during the electrolysis of dilute ZnCI₂ solution is?

Aionization

Boxidation

Creduction

Drecombination

View Explanation & Discuss

Question 848

jamb 1995

How many moles of copper would be deposited by passing 3F of electricity through a solution of copper (II) tetraoxosulpohate (IV)?

(F = 96 500 C mol^-)

A0.5

B1.0

C1.5

D3.0

View Explanation & Discuss

Question 849

jamb 1995

In the process of silver-plating a metal M, the metal M is the?

Aanode and a direct current is used

Bcathode and an alternating current is used

Canode and an alternating current is used

Dcathode and a direct current is used

View Explanation & Discuss

Question 850

jamb 1995

Neutralization involves a reaction between H₃O⁺ and?

ACI^-

BOH^-

CNO₃^-

DCO₃^2-

View Explanation & Discuss

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