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Chemistry Past Questions and Answers
Topic: Tests for oxidizing and reducing agents
Classroom
Jamb
Exam year:
Exam year
1978
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2020
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2023
Question type:
Question type
Objective
Theory
Topics:
Topics
[1] Separation of mixtures and purification of chemical substances
[1].1 Pure and impure substances
[1].2 Boiling and melting points
[1].3 Elements, compounds and mixtures
[1].4 Chemical and physical changes
[1].5 Separation processes
[1].5.1 Evaporation
[1].5.2 Simple and fractional distillation
[1].5.3 Sublimation
[1].5.4 Filtration
[1].5.5 Crystallization
[1].5.6 Paper and column chromatography
[1].5.7 Simple and fractional crystallization
[1].5.8 Magnetization
[1].5.9 Decantation
[2] Chemical combination
[2].1 Laws of definite, multiple and reciprocal proportions
[2].2 Law of conservation of matter
[2].3 Gay Lussac's law of combining volumes
[2].4 Avogadro's law
[2].4.1 Chemical symbols
[2].4.2 Formulae
[2].4.3 Avogadro's law - equations and their uses
[2].4.4 Relative atomic mass based on C=12
[2].4.5 The mole concept and Avogadro's number
[2].4.6 Stoichiometry of reactions
[3] Kinetic theory of matter and Gas Laws
[3].1 Phenomena to support the kinetic theory of matter using
[3].1.1 Melting
[3].1.2 Vapourization
[3].1.3 Boiling
[3].1.4 Freezing
[3].1.5 Condensation in terms of molecular motion and Brownian movement
[3].2 The laws of Boyle
[3].3 The laws of Charles
[3].4 Graham and Dalton (law of partial pressure)
[3].5 Combined gas law
[3].6 Molar volume and atomicity of gases
[3].7 The ideal gas equation
[3].8 The relationship between vapour density of gases and the relative molecular mass
[4] Atomic structure and bonding
[4].1 The concept of atoms, molecules and ions
[4].2 The works of:
[4].2.1 Dalton
[4].2.2 Millikan
[4].2.3 Rutherford
[4].2.4 Moseley
[4].2.5 Thompson
[4].2.6 Bohr
[4].3 Atomic structure
[4].4 Electron configuration
[4].5 Atomic number
[4].6 Mass number
[4].7 Isotopes
[4].8 Shapes of s and p orbitals
[4].9 The periodic table and periodicity of elements
[4].9.1 Presentation of the periodic table with a view to recognizing families of elements - alkali metals
[4].9.2 Presentation of the periodic table with a view to recognizing families of elements - halogens
[4].9.3 Presentation of the periodic table with a view to recognizing families of elements - the noble gases
[4].9.4 Presentation of the periodic table with a view to recognizing families of elements - transition metals
[4].9.5 The variation of ionization energy
[4].9.6 The variation of ionic radii
[4].9.7 The variation of electron affinity
[4].9.8 The variation of electronegativity
[4].10 Chemical bonding
[4].10.1 Electrovalency and covalency
[4].10.2 The electron configuration of elements and their tendency to attain the noble gas structure
[4].10.3 Hydrogen bonding and metallic bonding as special types of electrovalency and covalency
[4].10.4 Coordinate bond as a type of covalent bond
[4].10.5 Van der Waals' forces should be mentioned as a special type of bonding forces
[4].11 Shapes of simple molecules
[4].11.1 Linear ((H, O, Cl,HCl and CO)
[4].11.2 Non-linear (HO) and tetrahedral
[4].11.3 (CH) and pyramidal (NH)
[4].12 Nuclear Chemistry
[4].12.1 Radioactivity
[4].12.1.1 Types and properties of radiations
[4].12.2 Nuclear reactions
[4].12.2.1 Simple equations
[4].12.2.2 uses and applications of natural and artificial radioactivity.
[5] Air
[5].1 The natural gaseous constituents and their proportion in the air
[5].1.1 Nitrogen
[5].1.2 Oxygen
[5].1.3 Water vapour
[5].1.4 Carbon (IV) oxide
[5].1.5 The noble gases (argon and neon)
[5].2 Air as a mixture and some uses of the noble gas
[6] Water
[6].1 Water as a product of the combustion of hydrogen and its composition by volume.
[6].2 Water as a solvent
[6].2.1 Atmospheric gases dissolved in water and their biological significance.
[6].3 Hard and soft water
[6].3.1 Temporary and permanent hardness and methods of softening hard water
[6].4 Treatment of water for town supply
[6].5 Water of crystallization
[6].5.1 Efflorescence
[6].5.2 Deliquescence and hygroscopy
[6].5.3 Examples of the substances exhibiting these properties and their uses.
[7] Solubility
[7].1 Unsaturated, saturated and supersaturated solutions
[7].1.1 Solubility curves and simple deductions from them
[7].1.2 Solubility defined in terms of mole per dm
[7].1.3 Simple calculations
[7].2 Solvents for fats, oil and paints
[7].2.1 The use of such solvents for the removal of stains
[7].3 True and False solution (Suspensions and colloids)
[7].3.1 Properties and examples
[7].3.2 Harmattan haze and water paints as examples of suspensions and fog
[7].3.3 Milk
[7].3.4 Aerosol spray
[7].3.5 Emulsion paints
[7].3.6 Rubber solution as examples of colloids
[8] Environmental Pollution
[8].1 Sources and effects of pollutants
[8].2 Air pollution
[8].2.1 Examples of air pollutants such as H₂S, CO, SO₂, oxides of nitrogen, chlorofluorocarbons and dust
[8].3 Water pollution
[8].3.1 Sewage and oil pollution should be known
[8].4 Soil pollution
[8].4.1 Oil spillage
[8].4.2 Biodegradable pollutants
[8].4.3 Non-biodegradable pollutants
[9] Acids, bases and salts
[9].1 General characteristics and properties of acids
[9].2 General characteristics and properties of Bases and salts
[9].3 Acids/base indicators
[9].4 Basicity of acids
[9].5 Normal, acidic, basic and double salts
[9].6 An acid defined as a substance whose aqueous solution furnishes H3O+ ions or as a proton donor
[9].7 Ethanoic, Citric and tartaric acids as examples of naturally occurring organic acids
[9].8 Alums as examples of double salts
[9].9 Preparation of salts by neutralization
[9].10 Precipitation and action of acids on metals
[9].11 Oxides and trioxocarbonate (IV) salts
[9].12 Qualitative comparison of the conductances of molar solutions of strong and weak acids and bases
[9].13 Relationship between conductance and amount of ions present
[9].14 pH and pOH scale
[9].14.1 Simple calculations
[9].15 Acid/base titrations
[9].16 Hydrolysis of salts
[9].16.1 Simple of Hydrolysis Of Salts examples such as NH₄Cl, AlCl₃, Na₂CO₃, CH₃COONa
[10] Oxidation and Reduction - Redox
[10].1 Oxidation in terms of the addition of oxygen or removal of hydrogen
[10].2 Reduction as removal of oxygen or addition of hydrogen
[10].3 Oxidation and reduction in terms of electron transfer
[10].4 Use of oxidation numbers
[10].5 IUPAC nomenclature of inorganic compounds using oxidation number
[10].6 Tests for oxidizing and reducing agents
[11] Electrolysis
[11].1 Electrolytes and non-electrolytes
[11].1.1 Faraday's laws of electrolysis
[11].2 Electrolysis of dilute H₂SO₄
[11].3 Aqueous CuSO₄
[11].4 CuCl₂ solution
[11].5 Dilute and concentrated NaCl solutions
[11].6 Fused NaCl
[11].7 Factors affecting discharge of ions at the electrodes
[11].8 Uses of electrolysis
[11].8.1 Purification of metals
[11].9 Electrochemical cells
[11].9.1 Electrochemical series (K, Ca,Na, Mg, Al, Zn, Fe, Sn, Pb, H, Cu, Hg, Ag, Au,)
[11].9.2 half-cell reactions and electrode potentials.
[11].10 Corrosion as an electrolytic process
[11].10.1 Cathodic protection of metals
[11].10.2 Painting as ways of preventing iron from corrosion.
[11].10.3 Electroplating and coating with grease as ways of preventing iron from corrosion.
[12] Energy changes
[12].1 Energy changes ∆H accompanying physical and chemical changes
[12].1.1 Dissolution of substances in/or reaction with water
[12].2 Entropy as an order-disorder phenomenon
[12].2.1 Simple illustrations like mixing of gases and dissolution of salts.
[12].3 Spontaneity of reactions
[12].3.1 ΔG° = 0 as a criterion for equilibrium
[12].3.2 ∆G greater or less than zero as a criterion for non-spontaneity or spontaneity
[13] Rates of Chemical Reaction
[13].1 Elementary treatment of the following factors which can change the rate of a chemical reaction
[13].1.1 Temperature
[13].1.2 Concentration/Pressure
[13].1.3 Surface area
[13].1.4 Catalyst
[13].2 Reaction rate curves
[13].3 Activation energy
[13].3.1 Qualitative treatment of Arrhenius' law and the collision theory
[13].3.2 Effect of light on some reactions
[14] Chemical equilibra
[14].1 Reversible reactions and factors governing the equilibrium position
[14].2 Dynamic equilibrium
[14].3 Le Chatelier's principle and equilibrium constant
[15] Non-metals and their compounds
[15].1 Hydrogen
[15].1.1 Commercial production from water gas and cracking of petroleum fractions
[15].1.2 Laboratory preparation
[15].1.3 Properties, uses and test for hydrogen
[15].2 Halogens
[15].2.1 Chlorine as a representative element of the halogen
[15].2.2 Laboratory preparation
[15].2.3 Industrial preparation by electrolysis, properties and uses
[15].2.4 Hydrogen chloride and Hydrochloric acid
[15].2.5 Chlorides and test for chlorides
[15].3 Oxygen and Sulphur
[15].3.1 Oxygen
[15].3.1.1 Laboratory preparation, properties and uses
[15].3.1.2 Commercial production from liquid air
[15].3.1.3 Oxides: Acidic, basic, amphoteric and neutral
[15].3.1.4 Trioxygen (ozone) as an allotrope and the importance of ozone in the atmosphere
[15].3.2 Sulphur
[15].3.2.1 Uses and allotropes
[15].3.2.2 Preparation, properties and uses of sulphur (IV) oxide
[15].3.2.3 the reaction of SO2 with alkalis.
[15].3.2.4 Trioxosulphate (IV) acid and its salts
[15].3.2.5 Tetraoxosulphate(VI) acid
[15].3.2.5.1 Commercial preparation (contact process only)
[15].3.2.5.2 properties as a dilute acid
[15].3.2.5.3 An oxidizing and a dehydrating agent and uses
[15].3.2.5.4 Test for SO₄²⁻
[15].3.2.6 Hydrogen sulphide
[15].3.2.6.1 Preparation and properties as a weak acid
[15].3.2.6.2 reducing and precipitating agents
[15].3.2.6.3 Test for S²⁻
[15].4 Nitrogen
[15].4.1 Laboratory preparation
[15].4.2 Production from liquid air
[15].4.3 Ammonia
[15].4.3.1 Laboratory and industrial preparations (Haber Process only)
[15].4.3.2 properties and uses
[15].4.3.3 ammonium salts and their uses
[15].4.3.4 oxidation of ammonia to nitrogen (IV) oxide and trioxonitrate (V) acid
[15].4.3.5 Test for NH₄⁺
[15].4.4 Trioxonitrate (V) acid
[15].4.4.1 Laboratory preparation from ammonia
[15].4.4.2 properties and uses..
[15].4.4.3 Trioxonitrate (V) salt - action of heat and uses.
[15].4.4.4 Test for NO₃⁻
[15].4.5 Oxides of nitrogen
[15].4.5.1 Properties.
[15].4.5.2 The nitrogen cycle
[15].5 Carbon
[15].5.1 Allotropes - Uses and properties
[15].5.2 Carbon(IV) oxide
[15].5.2.1 Laboratory preparation, properties and uses,,
[15].5.2.2 Action of heat on trioxocarbonate (IV) salts and test for CO₃²⁻
[15].5.3 Carbon(II) oxide
[15].5.3.1 Laboratory preparation, properties including its effect on blood
[15].5.3.2 sources of carbon (II) oxide to include charcoal, fire and exhaust fumes.
[15].5.4 Coal
[15].5.4.1 Different types
[15].5.4.2 products obtained from destructive distillation of wood and coal.
[15].5.5 Coke
[15].5.5.1 Gasification and uses.
[15].5.5.2 Manufacture of synthesis gas and uses.
[16] Metals and their compounds
[16].1 General properties of metals
[16].2 Alkali metals
[16].2.1 Sodium hydroxide
[16].2.2 Sodium trioxocarbonate (IV) and sodium hydrogen trioxocarbonate (IV)
[16].2.3 Sodium chloride
[16].3 Alkaline-earth metals
[16].3.1 Properties and uses of Alkaline-earth
[16].3.2 Preparation of calcium oxide from sea shells
[16].3.3 The chemical composition of cement and the setting of mortar
[16].4 Aluminium
[16].4.1 Purification of bauxite
[16].4.2 Electrolytic extraction
[16].4.3 Properties and uses of aluminium and its compounds
[16].5 Tin
[16].5.1 Extraction from its ores
[16].5.2 Properties and uses
[16].6 Metals of the first transition series, Characteristic properties
[16].6.1 Electron configuration
[16].6.2 Oxidation states
[16].6.3 Complex ion formation
[16].6.4 Formation of coloured ions
[16].6.5 Catalysis
[16].7 Iron
[16].7.1 Extraction from sulphide and oxide ores
[16].7.2 Properties and uses of Iron
[16].7.3 Different forms of iron and their properties and advantages of steel over iron
[16].8 Copper
[16].8.1 Extraction from sulphide and oxide ores.
[16].8.2 Properties and uses of copper
[16].8.3 Preparation and uses of copper(II) tetraoxosulphate(VI)
[16].8.4 Test for Cu²⁺
[16].9 Alloy
[16].9.1 Steel, stainless steel, brass, bronze (constituents and uses only).
[16].9.2 type-metal, duralumin, soft solder, permallory and alnico (constituents and uses only).
[17] Organic Compounds
[17].1 Aliphatic hydrocarbons
[17].1.1 Alkanes
[17].1.1.1 Homologous series in relation to physical properties
[17].1.1.2 Substitution reaction and a few examples and uses of halogenated products
[17].1.1.3 Isomerism - structural only
[17].1.1.4 Petroleum - composition, fractional distillation and major products
[17].1.1.5 Petrochemicals - starting materials of organic syntheses, quality of petrol and meaning of octane number
[17].1.2 Alkenes
[17].1.2.1 Isomerism: structural and geometric isomerism
[17].1.2.2 additional and polymerization reactions
[17].1.2.3 polythene and synthetic rubber as examples of products of polymerization and its use in vulcanization.
[17].1.3 Alkynes
[17].1.3.1 Ethyne – production from action of water on carbides, simple reactions and properties of ethyne.
[17].2 Aromatic hydrocarbons
[17].2.1 Benzene - structure, properties and uses
[17].3 Alkanols
[17].3.1 Primary, secondary, tertiary - production of ethanol by fermentation and from petroleum by-products
[17].3.2 Local examples of fermentation and distillation
[17].3.3 Reactions of OH group
[17].4 Alkanals and alkanones
[17].4.1 Chemical test to distinguish between alkanals and alkanones
[17].5 Alkanoic acids
[17].5.1 Chemical reactions
[17].5.2 Neutralization and esterification
[17].5.3 Ethanedioic (oxalic) acid as an example of a dicarboxylic acid and benzene carboxylic acid as an example of an aromatic acid.
[17].6 Alkanoates
[17].6.1 Formation from alkanoic acids and alkanols
[17].6.2 Saponification
[17].6.2.1 Production of soap and margarine from alkanoates and distinction between detergents and soaps.
[17].7 Amines (Alkanamines) Primary, Secondary, and tertiary
[17].8 Carbohydrates
[17].8.1 Classification – mono-, di- and polysaccharides; composition, chemical tests for simple sugars and reaction with concentrated tetraoxosulphate (VI) acid
[17].8.2 Hydrolysis of complex sugars
[17].8.3 the uses of sugar and starch in the production of alcoholic beverages, pharmaceuticals and textiles.
[17].9 Proteins
[17].9.1 Primary structures, hydrolysis and tests (Ninhydrin, Biuret, Millon’s and xanthoproteic)
[17].9.2 Enzymes and their functions
[17].10 Polymers
[17].10.1 Natural and synthetic rubber
[17].10.2 Addition and condensation polymerization
[17].10.3 Methods of preparation, examples and uses.
[17].10.4 Thermoplastic and thermosetting plastics
[18] Chemistry and Industry
[18].1 Chemical industries
[18].1.1 Types of Chemical industries
[18].1.2 Raw materials of Chemical industries
[18].1.3 Relevancies of Chemical industries
[18].1.4 Biotechnology
Jamb Chemistry Questions - Tests for oxidizing and reducing agents
Question 6:
JAMB 1998
Mg
2+
(aq)
+ 2e
-
>
(aq)
→ Mg
(s)
E°
(volts)
= 2.370
Zn
2+
(aq)
+ 2e
-
>
(aq)
→ Zn
(s)
E°
(volts)
= -0.763
Cds
2+
(aq)
+ 2e
-
>
(aq)
→ Cd
(s)
E°
(volts)
= 0.403
Cu
2+
(aq)
+ 2e
-
>
(aq)
→ Cu
(s)
E°
(volts)
= 0.340
In the electrochemical series above, the strongest reducing agents is?
SchoolNGR Classroom
A
Cu <sub style='font-size: smaller;'>(s)</sub>
B
Cd<sub style='font-size: smaller;'>(s)</sub>
C
Znsub>(s)
D
Mg<sub style='font-size: smaller;'>(s)</sub>
View Answer & Explanation
Question 7:
JAMB 2003
If y is an oxidizing agent that reacts with a reducing agent, Z, which of the following is correct?
SchoolNGR Classroom
A
Y increases in oxidation number
B
Y becomes reduced
C
Z loses protons
D
Z gains protons
View Answer & Explanation
Question 8:
JAMB 2006
The ion that can be used as an oxidizing agent is
SchoolNGR Classroom
A
Au<sup style='font-size: smaller;'>3+</sup>
B
Fe<sup style='font-size: smaller;'>3+</sup>
C
ClO<sup style='font-size: smaller;'>-</sup>
D
Ca<sup style='font-size: smaller;'>2+</sup>
View Answer & Explanation
Question 9:
JAMB 2009
The colour changes observed when testing for reducing agents using acidified potassium heptaoxodichromate (IV) solution is
SchoolNGR Classroom
A
Yellow to purple
B
Orange to green
C
Green to orange
D
Purple to yellow
View Answer & Explanation
Question 10:
JAMB 2019
If acidified Potassium Dichromate(VI) (K\(_2\)Cr\(_2\)O\(_7\)) acts as oxidizing agent, color changes from
SchoolNGR Classroom
A
Yellow to green
B
Orange to green
C
Yellow to red
D
Orange to red
View Answer & Explanation
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