Chemistry 2020 Past Questions | WAEC

Study the following Chemistry past questions and answers for JAMBWAEC  NECO and Post-JAMB. Get prepared with official past questions and answers for upcoming examinations.

16. A factor that is considered most important when siting a chemical industry is?

  • A. nearness to other industrial establishments
  • B. nearness to raw materials
  • C. favourable climate conditions
  • D. availability of storage facilities

17.  The boiling point of pentane is higher than that of propane because?

  • A. carbon-carbon single bonds are stronger than carbon-hydrogen bonds.
  • B. Pentane has more covalent bonds to break
  • C. Pentane does not burn easily as propane
  • D. The intermolecular forces in pentane are stronger than those of propane

18. Which of the following solids would not decompose on heating?

  • A. Ammonium chloride
  • B. Lead (i) trioxonitrate (V)
  • C. Potassium trioxocarbonate (IV)
  • D. Sodium hydrogen trioxocarbonate (IV)

19.  The following molecules have double covalent bonds between two atoms except?

  • A. oxygen
  • B. carbon (IV)oxide
  • C. ethene
  • D. water

20. The type of isomerism exhibited by cis and trans isomers is?

  • A. positional
  • B. geometrical
  • C. functional
  • D. optical

21.  Which of the following compounds has the lowest boiling point?

  • A. C4H10
  • B. CH3COOH
  • C. H2O
  • D. C2H5OH

22. An alkanol containing 60% carbon by mass would have a molecular formula [H=1.0. C-12.0, O= 16.0]

  • A. CH3OH
  • B. C2H5OH
  • C. C3H7OH
  • D. C4H9OH

23. Which of the following compounds would release hydrogen when reacted with sodium metal? 

  1. CH3COOH
  2. CH3CH2OH


  • A. I only
  • B. I and II only
  • C. Il and IIl only

D. I and Ill only

24.  Which of the following substances is not a reducing agent?

  • A. C
  • B. CO
  • C. O2
  • D. H2

25.  Which of the following statements is correct for a reaction at equilibrium?

  • A. All reactions cease to occur
  • B. The reaction has gone to completion
  • C. The rates of the forward and backward reactions are equal
  • D. The amount of product equals the amount of reactants

26. Which of the following reactions are always exothermic? 1. Neutralization Il. Decomposition III. Combustion

  • A. I and II only
  • B. I and III only
  • C. II and IIl only
  • D. I, II and III

27. Which of the following standard conditions is not correct about energy changes?

  • A. Standard temperature is 298K
  • B. B. Standard pressure is 1 atm
  • C. Concentration of solution must be 1 mol/dm33
  • D. ΔH at 298 K is the activation energy

28.  f 5.0 cm−3of 0.200 mol dm-3Na2CO3 was diluted to 250cm-3 solution, what would be the concentration of the resulting solution?

  • A. 0.004 mol dm-3 
  • B. 0.020 mol dm-3 
  • C. 0.200 mol dm-3 
  • D. 0.400 mol dm-3 

29. The initial volume and pressure of a given mass of gas is V and 3.P. What is its pressure if its volume is increased to  2V at constant temperature?

  • A. 3 P
  • B. 2P
  • C. 3/2P
  • D. 2/3 P

30. What volume of oxygen at s.t.p is required to burn completely 7.5 dm33of methane according to the following equation?

CH4 g + 202 g  → CO2 g + H2Og

  • A. 3.75 dm3
  • B. 7.59 dm3
  • C. 15.0 dm3
  • D. 30.0dm3

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