JAMB Chemistry Past Questions & Answer 2020: (Read & Download PDF)

JAMB Chemistry Past Questions & Answer 2020: (Read & Download PDF): The Joint Admissions and Matriculations Board (JAMB) is a Nigerian entrance examination board for tertiary-level institutions. The board conducts entrance examinations for prospective undergraduates into Nigerian universities.

Am very sure if you study these questions really well, You will definitely pass the JAMB 2020/2021 examination. The secret to passing any exam is intensive study. That said, getting a high score in Jamb is what every Jamb candidate desires but some candidate’s expectations do not come into reality.

I won’t advise you to cram these questions on your head, my advice is you study it and also read on the topics of this questions well, make sure you touch as many examples on the textbooks recommended by JAMB here


1. Which of the following statements is NOT correct?
  • A. The average kinetic energy of a gas is directly proportional to its temperature
  • B. At constant temperature, the volume of a gas increases as the pressure increases
  • C. The pressure of a gas is inversely proportional to its volume
  • D. The temperature of a gas is directly proportional to its volume
  • E. The collisions of molecules with each other are inelastic
Zinc Oxide is a
  • A. Basic Oxide
  • B. Acidic Oxide
  • C. Amphoteric Oxide
  • D. Neutral Oxide
  • E. Reactive Oxide

When sodium chloride and metallic sodium are each dissolved in water

  • A. both processes are exothermic
  • B. both processes are endothermic
  • C. the dissolution of metallic sodium is endothermic
  • D. the dissolution of metallic sodium is exothermic
  • E. the dissolution of sodium chloride is explosive
The periodic classification of elements is an arrangement of the elements in order of their
  • A. Atomic Weights
  • B. Isotopic Weights
  • C. Molecular Weights
  • D. Atomic Numbers
  • E. Atomic Masses



In the reaction between sodium hydroxide and sulphuric acid solutions, what volume of 0.5 molar sodium hydroxide would exactly neutralise 10cm3 of 1.25 molar sulphuric acid?

  • A. 5cm3
  • B. 10cm3
  • C. 20cm3
  • D. 25cm3
  • E. 50cm3


Hydrogen diffuses through a porous plug

  • A. at the same rate as oxygen
  • B. at a slower rare than oxygen
  • C. twice as fast as oxygen
  • D. three times as fast as oxygen
  • E. four times as fast as oxygen.


If the molar mass of X is 36 g, the number of moles of X dissolved at 343 is

  • A. 0.2 moles
  • B. 0.7 moles
  • C. 1.5 moles
  • D. 2.0 moles
  • E. 3.0 moles.


Hydrogen diffuses through a porous plug

  • A. at the same rate as oxygen
  • B. at a slower rare than oxygen
  • C. twice as fast as oxygen
  • D. three times as fast as oxygen
  • E. four times as fast as oxygen.


A certain volume of a gas at 298K is heated such that its volume and pressure are now four times the original values. What is the new temperature?

  • A. 18.6 K
  • B. 100.0 K
  • C. 298.0 K
  • D. 1192.0 K
  • E. 47689.0 K.


A correct electrochemical series can be obtained from K, Na, Ca, Al, Mg, Zn, Fe, Pb, H, Cu, Hg, Ag, Au by interchanging

  • A. Al and Mg
  • B. Zn and Fe
  • C. Zn and Pb
  • D. Pb and H
  • E. Au and Hg.


The boiling points of water, ethanol, toluene and button-2-ol are 373.OK, 351.3K, 383.6 K and 372.5 K respectively. Which liquid has the highest vapour pressure at 323.0K?

  • A. water
  • B. Toluene
  • C. Ethanol
  • D. Butan-2-ol
  • E. None.


2MnO4- + 10Cl- + 16H + ’! 2Mn2+ + 5Cl2 + 8H2O. which of the substances serves as an oxidizing agent?

  • A. Mn2+
  • B. ClC. H2O
  • D. MnO4
  • E. Cl2.


which of the following metals will displace iron from a solution of iron(11) tetraoxosulphate(1V)?

  • A. copper
  • B. mercury
  • C. silver
  • D. Zinc
  • E. Gold.


Complete hydrogenation of ethyne yields

  • A. benzene
  • B. methane
  • C. ethene
  • D. propane
  • E. Ethane.


What is the formula of sodium gallate if gallium (Ga) shows an oxidation number of +3.

  • A. NaGaO3
  • B. Na2G(OH)2
  • C. NaGa(OH)3
  • D. NaGa (OH)4
  • E. NaGaO.


Complete hydrogenation of ethyne yields

  • A. benzene
  • B. methane
  • C. ethene
  • D. propane
  • E. Ethane.


Which of the following is used in the manufacture of bleaching powder?

  • A. sulphur dioxide
  • B. chlorine
  • C. hydrogen tetraoxosulphate
  • D. hydrogen sulphide
  • E. nitrogen dioxide.


Tetraoxosulphate (V1) ions are finally tested using

  • A. acidified silver nitrate
  • B. acidified barium chloride
  • C. lime – water
  • D. dilute hydrochloric acid
  • E. acidified lead nitrate.


Mixing of aqueous solution of barium hydroxide and sodium tetraoxocarbonate(1V) yields a white precipitate of

  • A. barium oxide
  • B. sodium tetraoxocarbonate(1V)
  • C. sodium, oxide
  • D. sodium hydroxide
  • E. barium trioxocarbonate.


An organic compound decolourises acidified KMnC4 solution but failed to react with ammoniacal silver nitrate solution. The organic compound is likely to be.

  • A. a carbonxyllic acicd
  • B. an alkane
  • C. an alkene
  • D. an alkyne
  • E. an alkanone.


Solid sodium hydroxide on exposure to air absorbs a gas and ultimately gives another alkaline substance with the molecular formula.

  • A. NaOH.H2O
  • B. NaOH.N2
  • C. Na2CO3
  • D. NaHCO3
  • E. NaNO3.


The neutralization reaction between NaOH solution and nitrogen (1V) oxide (NO2) produces water and

  • A. NaNO2 and NaNO3
  • B. NaNO3 and HNO3
  • C. NaNO2
  • D. NaNO3
  • E. NaN2O3.


Which of the following substances is the most abundant in the universe?

  • A. Carbon
  • B. Air
  • C. Water
  • D. Oxygen
  • E. Hydrogen.


Addition of dilute hydrochloric acid to an aqueous solution of a crystalline salt yielded a yellow precipitate and a gas which turned dichromate paper green. The crystalline salt was probably

  • A. Na2SO4
  • B. Na2S
  • C. NaS2O3.5H2O
  • D. NaCO3
  • E. NaHCO3.


The process involved in the conversion of an oil into margarine is known as

  • A. hydrogenation
  • B. condensation.
  • C. hydrolysis
  • D. dehydration
  • E. cracking.


Compound X is

  • A. an alkene
  • B. an alkane
  • C. an alkyne
  • D. tetra chloromethane
  • E. Dichloromethane.


Which of the following roles does sodium chloride play in soap preparation? It

  • A. reacts with glycerol
  • B. purifies the soap
  • C. accelerates the decomposition of the fat and oil
  • D. separates the soap form the glycerol
  • E. converts the fat acid to its sodium salt.


The atomic number of an element whose caution, X2+, has the ground state electronic configuration is Is22s22P63s22p6 is

  • A. 16
  • B. 18
  • C. 20
  • D. 22
  • E. 24.


Which of the following sulphides is insoluble in dilute HCl?

  • A. Na2S
  • B. ZnS
  • C. CuS
  • D. FeS.


When chlorine is passes into water and subsequently exposed to sunlight, the gas evolved is

  • A. HCl
  • B. HOCl
  • C. O2
  • D. Cl2O2.


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

  • A. KCl
  • B. NaNO3
  • C. K2SO
  • D. CaSO4.


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

  • A. oxidized to ethene
  • B. polymerized to polyethene
  • C. dehydrated to ethene
  • D. dehydrated to ethyne.


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

  • A. Electrolysis of the solution of its salt
  • B. Decomposition of its oxide
  • C. Displacement from solution by an alkali metal
  • D. Electrolysis of fused salt.


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

  • A. Nylon and soap
  • B. Nylon and rubber
  • C. Soap and butane
  • D. Margarine and Nylon.


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

  • A. Tetramethyl silane
  • B. Lead tetra-ethyl
  • C. Glycerol
  • D. N-heptanes.


Starch can converted to ethyl alcohol by

  • A. distillation
  • B. fermentation
  • C. isomerization
  • D. cracking.


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

  • A. Neutralization
  • B. Saponification
  • C. Etherification
  • D. Salting-out.


In the purification of town water supply, alum is used principally to .

  • A. kill bacteria
  • B. control the pH of water
  • C. improve the taste of the water
  • D. coagulate small particles of mud.


Oil spillage in ponds and creeks can be cleaned up by

  • A. burning off the oil layer
  • B. spraying with detergent
  • C. dispersal with compressed air
  • D. spraying with hot water.


Which of the following substances has the lowest vapour density?

  • A. Ethanoic acid
  • B. Propanol
  • C. Dichlomethane
  • D. Ethanal [O = 16, Cl = 35.5, H =1, C = 12].


In which of the following pairs of elements is allotropy exhibited by each element?

  • A. Phosphorus and hydrogen
  • B. Oxygen and chlorine
  • C. Sulphur and nitrogen
  • D. Oxygen and sulphur.


ethanol reacts with aqueous sodium mono-oxoio date(1) to gives a bright yellow solid with a characteristic smell. The products is

  • A. trichlomethane
  • B. ftriiodomethane
  • C. iodoethane
  • D. ethanol


Stainless steel is an alloy of

  • A. iron, carbon and silver
  • B. ironm carbon and lead
  • C. iron, carbon and chromium
  • D. iron and carbon only.


Corrosion is exhibited by.

  • A. iron only
  • B. electropositive metals
  • C. metals below hydrogen in the electrochemical series
  • D. all metals.


Some products of destructive distillation of coal are

  • A. carbon (iV) oxide and ethanoic acid
  • B. trioxocarbonate (lV) acid and methanoic acid
  • C. producer gas and water gas
  • D. coke and ammonia liquor.


Gunpowder is made from charcoal, sulphur and potassium trioxonirate (V). The salt in the mixture performs the function of

  • A. an oxidant
  • B. a reductant
  • C. a solvent
  • D. a catalyst.


The reaction between ethanoic acid and sodium hydroxide is an example of

  • A. esterification
  • B. neutralization
  • C. hydrosylation
  • D. hydrolysis.

48. The bond which joins two ethanoic acid molecules in the liquid state is

  • A. a covalent bond
  • B. an ionic bond
  • C. a dative covalent bond
  • D. a hydrogen bond.


The product of the thermal decomposition of ammonium trioxonirate (V) are.

  • A. NO2 and oxygen
  • B. NH3 and oxygen
  • C. nitrogen and water
  • D. N2O and water.


The alkaline hydrolysis of fats and oils produces soap and

  • A. propane 1, 1, 3-triol
  • B. propane – 1, 3, 3-triol
  • C. propane-1-2-2-triol
  • D. propane-1-2-3-triol.

RECOMMENDED: Materials you need to prepare for the JAMB 2020/2021 to succeed 

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Thanks for this, very explanatory and I will work hard to cover all of this. May God help me Amen☺


Wow, thanks for this sir, God bless you for the advice also



ELLU Sylvester

Okay ,continue


Buh the answer for this chemistry is not there

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