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JAMB Chemistry 2016 Objective Past Questions

All 40 questions from the Joint Admissions and Matriculation Board (JAMB) Chemistry 2016 Objective paper, with the correct answer and a full explanation for each. Free, no signup needed.

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Chemistry 2016 Objective — Question 1

The compound CH3-C(OH)-COOH exhibits a geometric isomerism

  • A. geometric isomerism
  • B. positional isomerism
  • C. structural isomerism
  • D. optical isomerismCorrect

Explanation

The compound exhibits optical isomerism.

Chemistry 2016 Objective — Question 2

MnO4-(aq) + Y + 5Fe2+(aq) → Mn2+(aq) + 5Fe3+(aq) + 4H2O. In the equation above, is

  • A. 10H+
  • B. 5H+
  • C. 8H+Correct
  • D. 4H+

Explanation

The balanced equation for the redox reaction between Fe2+ and MnO4- in acidic medium requires 8H+.

Chemistry 2016 Objective — Question 3

In an electrochemical cell, polarization is caused by A. oxygen B. hydrogenC. tetraoxosulphate VI acid D. chlorine

  • A. oxygen
  • B. hydrogenCorrect
  • C. tetraoxosulphate VI acid
  • D. chlorine

Explanation

Polarization results from the accumulation of hydrogen. This can be rectified using a depolarizer such as manganese (IV) oxide, MnO2.

Chemistry 2016 Objective — Question 4

The condition required for corrosion to take place in the presence of

  • A. oxygen and carbon (IV) oxide
  • B. water and oxygen (IV) oxideCorrect
  • C. water, carbon (IV) oxide and oxygen
  • D. water and carbon (IV) oxide

Explanation

The presence of water and oxygen (IV) oxide is the condition required for corrosion to take place.

Chemistry 2016 Objective — Question 5

The enzyme used in the hydrolysis of starch to dextrin and maltose is

  • A. zymase
  • B. sucrase
  • C. amylaseCorrect
  • D. lactase

Explanation

The enzyme used in the hydrolysis of starch to dextrin and maltose is amylase.

Chemistry 2016 Objective — Question 6

The products formed when propanol is heated over a copper catalyst in the absence of oxygen are

  • A. CH3CH2CHO and H2Correct
  • B. CH3CHO and CO2
  • C. CH3CH2COOH and H2
  • D. CH3COOH and CO2

Explanation

The products formed when propanol is heated over a copper catalyst in the absence of oxygen are CH3CH2CHO and H2.

Chemistry 2016 Objective — Question 7

In the laboratory preparation of chlorine from concentrated hydrochloric acid in the presence of potassium tetraoxomanganate (VII) the gas produced is dried by passing it through

  • A. concentrated tetraoxosulphate (VI) acidCorrect
  • B. anhydrous calcium chloride
  • C. calcium oxide
  • D. sodium hydroxide

Explanation

The usual drying agent for chlorine is concentrated tetraoxosulphate (VI) acid.

Chemistry 2016 Objective — Question 8

Which of the following compounds is used as a gaseous fuel?

  • A. CH3-CH3-CHO2-COOH
  • B. CH3-C≡CH-CH2-CH3
  • C. CH3-CH2-CH3Correct
  • D. CH2-CH2-CH3(OH)

Explanation

Gases like methane, ethane, propane and butane are usually employed as gaseous fuels. Utilgas (the gas we use at home) is normally propane or butane that has been sufficiently pressurized.

Chemistry 2016 Objective — Question 9

Cast iron is used in making

  • A. chains and agricultural implements
  • B. iron sheets and retort stand
  • C. nails and iron rods
  • D. stoves and cookersCorrect

Explanation

Items which do not have to bear much strain such as stoves, cooker, pipes, radiators and Bunsen burner etc. are made of cast iron.

Chemistry 2016 Objective — Question 10

The monomer of nylon is

  • A. hydroxybenzene
  • B. hexanedioic acidCorrect
  • C. benzene-1,4-dicarboxylic acid
  • D. ethane-1,2-diols

Explanation

The monomers of nylon-6,6 are hexane-1,6-diamine and hexanedioic acid.

Chemistry 2016 Objective — Question 11

The principle of column chromatography is based on the ability of the constituents to

  • A. react with the solvent in the column
  • B. react with each other in the column
  • C. dissolve in each other in the column
  • D. move at different speeds in the columnCorrect

Explanation

Chromatography is based on the ability of the constituents to move at different speeds in the column.

Chemistry 2016 Objective — Question 12

Ammonium chloride can be separated from its mixture with common salt by

  • A. distillation
  • B. evaporation
  • C. decantation
  • D. sublimationCorrect

Explanation

Ammonium chloride can be separated from its mixture with common salt by sublimation. This is useful because ammonium chloride can sublime while common salt (NaCl) cannot.

Chemistry 2016 Objective — Question 13

H-C(H)(OH)-C(H)(H)-C(H)(H)-C(H)(Cl)H - The functional groups present in the compound above are

  • A. alkene and halo-group
  • B. hydroxyl and chloro-groupCorrect
  • C. alkene and chloro-group
  • D. hydroxyl and halo-group

Explanation

The functional groups present in the compound above are the hydroxyl group and chloro group.

Chemistry 2016 Objective — Question 14

The ability of carbon to form long chains is referred to as

  • A. alkylation
  • B. acylation
  • C. catenationCorrect
  • D. carbonation

Explanation

Carbon has the ability to form long chain using its own atoms. This is known as catenation.

Chemistry 2016 Objective — Question 15

Alkanols have the general molecular formula

  • A. CnH2n-2CHO
  • B. CnH2n2COC
  • C. CnH2n2OHCorrect
  • D. CnH2n2OH

Explanation

The general molecular formula for alkanols is CnH2n+1OH or ROH where R is the alkyl or aryl group.

Chemistry 2016 Objective — Question 16

The industrial preparation of hydrogen gas from water gas is referred to as

  • A. Bosch processCorrect
  • B. Contact process
  • C. Haber process
  • D. Bayer process

Explanation

The industrial preparation of hydrogen gas from water gas is known as the Bosch process, in honour of Carl Bosch who first prepared hydrogen this way.

Chemistry 2016 Objective — Question 17

The relative atomic mass of a naturally occurring lithium consisting 90% ⁷Li and 10% ⁶Li is

  • A. 6.2
  • B. 6.8
  • C. 7.1
  • D. 6.9Correct

Explanation

R.A.M = (Mass1×%1 + Mass2×%2)/100 = (7×90/100)+(6×10/100) = 6.3+0.6 = 6.9.

Chemistry 2016 Objective — Question 18

The colour of litmus in an alkaline medium is

  • A. red
  • B. yellow
  • C. pink
  • D. blueCorrect

Explanation

Litmus has a red colour in acidic solutions, purple colour in neutral solutions and blue colour in alkaline solutions.

Chemistry 2016 Objective — Question 19

n monosaccharide ⇌ Polysaccharide in water. In the process above, P and Q respectively represent

  • A. condensation and hydrolysisCorrect
  • B. fermentation and condensation
  • C. polymerization and hydrolysis
  • D. polymerization and condensation

Explanation

The conversion of a monosaccharide to a polysaccharide is by condensation while the reverse is by hydrolysis.

Chemistry 2016 Objective — Question 20

The compounds CH3CH2CHO and CH3COCH3 can be distinguished from each other using

  • A. dilute ammonia
  • B. Benedict's solution
  • C. Tollen's reagentCorrect
  • D. sodium hydroxide solution

Explanation

CH3CH2CHO (an aldehyde) and CH3COCH3 (a ketone) can be distinguished using Tollen's reagent, since aldehydes are able to reduce mild oxidizing agents such as Fehling's and Tollen's reagents while ketones are not.

Chemistry 2016 Objective — Question 21

Which of the following statements is true about 2-methylpropane and butane?

  • A. They have different number of carbon atoms
  • B. They are members of the same homologous seriesCorrect
  • C. They have the same boiling points
  • D. They have the same chemical properties

Explanation

2-methylpropane and butane are isomers. Since the two compounds differ only in the length of the continuous chain, their chemical properties are the same and they are members of the same homologous series.

Chemistry 2016 Objective — Question 22

N2O4(g) ⇌ 2NO2(g), ΔH = +ve. In the reaction above, an increase in temperature will

  • A. increase the reactant production
  • B. increase the value of the equilibrium constantCorrect
  • C. shift the equilibrium to the left
  • D. decrease the value of the equilibrium constant

Explanation

Since the forward reaction is endothermic, the backward reaction will be exothermic. Thus, a decrease in temperature favours the backward reaction (equilibrium position shifts to the left); an increase in temperature favours the forward reaction and increases the equilibrium constant.

Chemistry 2016 Objective — Question 23

The process that requires the use of a solution of hard water in its operation is

  • A. tanning
  • B. bottling
  • C. laundry
  • D. dyeingCorrect

Explanation

Although hard water usually gets in the way of many chemical processes (such as dyeing) because of the ions it contains, some processes are specially 'good-to-go' with hard water e.g. tannin.

Chemistry 2016 Objective — Question 24

What is the concentration of a solution containing 2g of NaOH in 100cm3 of solution? [Na = 23, O = 16, H = 1]

  • A. 6.05 moldm-3
  • B. 0.30moldm-3Correct
  • C. 0.50moldm-3
  • D. 0.40mol dm-3

Explanation

Mass of NaOH = 2g; Molar mass of NaOH = 40gmol-1; Mole = 2g/40gmol-1 = 0.05mol; Volume of solution = 100cm3 = 0.1dm3; Concentration = 0.05mol/0.1dm3 = 0.5moldm-3.

Chemistry 2016 Objective — Question 25

The radioisotope used in industrial radiography for the rapid checking of faults in welds and casting is

  • A. phosphorus-32
  • B. cobalt-60Correct
  • C. carbon-14
  • D. iodine-131

Explanation

Cobalt-60 is the radio isotope used in industrial radiography for the rapid checking of faults in welds and casting. The isotope is also used for destroying cancerous cells.

Chemistry 2016 Objective — Question 26

The compound produced when sodium is heated with excess sodium peroxide is

  • A. Na2CO3
  • B. Na2OCorrect
  • C. NaNO2
  • D. NaOH

Explanation

Sodium oxide is produced when sodium peroxide (Na2O2) is heated with excess sodium metal: Na2O2 + 2Na → 2Na2O.

Chemistry 2016 Objective — Question 27

The pollutant that contributes to the depletion of the ozone layer is

  • A. CFC(s)Correct
  • B. NO2
  • C. SO2
  • D. CO

Explanation

Chlorofluorocarbons (CFC's) are the major culprits when it comes to the depletion of ozone layer.

Chemistry 2016 Objective — Question 28

Which of the following properties is not peculiar to matter?

  • A. kinetic energy of particles increases from solid to gas
  • B. Random motion of particles increases from gas to solidCorrect
  • C. Orderliness of particles increases from gas to liquid
  • D. Random motion of particles increases from liquid to gas

Explanation

Random motion of particles increases from solid to gas and not the other way round.

Chemistry 2016 Objective — Question 29

In the diagram above, X is the

  • A. enthalpy
  • B. activated complex
  • C. activation energyCorrect
  • D. enthalpy change

Explanation

In the diagram, X is the activation energy.

Chemistry 2016 Objective — Question 30

The diagram represents

  • A. a spontaneous reaction
  • B. an exothermic reaction
  • C. a non-spontaneous reaction
  • D. an endothermic reactionCorrect

Explanation

The diagram (products at higher energy than reactants) represents an endothermic reaction.

Chemistry 2016 Objective — Question 31

Which of the following is not an alkali?

  • A. Ca(OH)2
  • B. NH3
  • C. NaOH
  • D. Al(OH)3Correct

Explanation

An alkali is a metallic hydroxide that is soluble in water. Examples of alkalis are NaOH and KOH. Ca(OH)2, Al(OH)3, Fe(OH)2, Fe(OH)3, NH4OH etc. are mere bases, not alkalis.

Chemistry 2016 Objective — Question 32

The curve depicts titration between (see pH graph).

  • A. strong acid and strong base
  • B. strong acid and weak base
  • C. weak acid and weak base
  • D. weak acid and strong baseCorrect

Explanation

Since the pH at the end point is less than 7, the curve represents the reaction between a weak acid and a strong base.

Chemistry 2016 Objective — Question 33

Which of the following statements is correct about the periodic table? A. Elements in the same group have the same number of electron shells B. The non-metallic properties of the elements tend to decrease across each period C. Elements in the same period have the same number of valence electrons D. The valence electrons of the elements iiyease progressively across the period

  • A. Elements in the same group have the same number of electron shells
  • B. The non-metallic properties of the elements tend to decrease across each period
  • C. Elements in the same period have the same number of valence electrons
  • D. The valence electrons of the elements increase progressively across the periodCorrect

Explanation

Elements in the same group have the same number of electrons at the outermost shell. The metallic character decreases across the period, while the non-metallic character does the opposite. Elements in the same period have the same number of electron shells. As we move from left to right across the periodic table, the valence electrons of the elements increase progressively.

Chemistry 2016 Objective — Question 34

The metal whose ore can be concentrated by passing it through a magnetic separator is

  • A. Zn
  • B. SnCorrect
  • C. Sb
  • D. Ca

Explanation

The ore of tin can be concentrated by passing it through a magnetic separator.

Chemistry 2016 Objective — Question 36

What volume of 0.5MH2SO4 will exactly neutralize 20cm3 of 0.1M NaOH solution?

  • A. 2.00cm3Correct
  • B. 5.00cm3
  • C. 6.8cm3
  • D. 8.3cm3

Explanation

2NaOH + H2SO4 → Na2SO4 + 2H2O; Mole of NaOH = 0.020dm3×0.1M = 0.002mol; mole of H2SO4 required = 0.001mol; V = 0.001/0.5 = 0.002dm3 = 2cm3.

Chemistry 2016 Objective — Question 37

Diamond cannot be used in

  • A. making bicycle chainsCorrect
  • B. abrasives
  • C. cutting glass and metals
  • D. dies for drawing wires

Explanation

Due to its hardness, diamond can be used as an abrasive, for cutting glass and metals as dies for drawing wires. The use of diamond does not include making of bicycle chains.

Chemistry 2016 Objective — Question 38

Ethanol owes its solubility/miscibility in/with water to its possession of

  • A. carbonyl group
  • B. hydroxyl groupCorrect
  • C. phenyl group
  • D. methyl group

Explanation

Ethanol is soluble in water due to the presence of a hydroxyl group.

Chemistry 2016 Objective — Question 39

CH4(g) + Cl2(g) → CH3Cl(l) + HCl(g). The major factor that influences the rate of the reaction above is

  • A. concentration
  • B. catalyst
  • C. temperature
  • D. lightCorrect

Explanation

This depicts a substitution reaction between an alkane and a halogen. The reaction is photo-catalyzed.

Chemistry 2016 Objective — Question 40

The number of electronic shells contained in an atom with electron configuration 1s²2s²2p⁶3s²3p⁶4s² is

  • A. 3
  • B. 2
  • C. 4Correct
  • D. 5

Explanation

1s2 2s2 2p6 3s2 3p6 4s2 = 20 electrons. The K, L, M, N shells structure will go as: 2, 8, 8, 2. Thus, the element has four shells.

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