Chemistry 2021 Past Questions | WAEC


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

  1. The hydrolysis of proteins by diluting mineral acids produces

    • A. sucrose
    • B. glucose
    • C. amino acids
    • D. fatty acids

2. Which of the following oxide causes acid rain?

  • A. CO
  • B. NO
  • C. H2O2
  • D. NO2

3. The ratio of carbon atoms of hydrogen atoms in a hydrocarbon is 1:2. If its molecular mass is 56, what is its molecular formula?

  • A. C3H6
  • B. C44H8
  • C. C22H4
  • D. CH2


What is the relative molecular mass of the compound below?+PwGSHWihfTqmAAAAAElFTkSuQmCC

[H = 1.0; C = 12.0; O = 16.0]

  • A. 137
  • B. 136
  • C. 64
  • D. 59

5. Cathodic protection of metals is based on

  • A. standard electrode potential of hydrogen
  • B. its electrical conductivity
  • C. nature of oxides formed
  • D. relative tendencies of oxidation

6. If humid air is polluted by chlorine discharged, the air can be restored by sprinkling

  • A. solid MnO2
  • B. acidified KMnO4
  • C. acidified FeSO4
  • D. saturated NaCl(aq)

7.  The alkanol represented by the structure below is?

  • A. primary and dihydric
  • B. secondary and monohydric
  • C. tertiary and dihydric
  • D. secondary and dihydric

8. Which of the following pairs of compounds would form a precipitate when their aqueous solutions are mixed?

  • A. NaCl and KNO3
  • B. KCL and NaNO3
  • C. K22SO4 and BaCl2
  • D. NH44NO3 and CO3

9. Study the graphs below and use them to answer the question below


Which of the following illustrates the variation of the rate of evolution of gas from a given length of magnesium ribbon (y-axis) with an increase in the concentration of the added (x-axis)?

  • A. I
  • B. II
  • C. III
  • D. IV

10. Which of the graphs illustrates the variation of the pH of a given volume of strong acid solution (y-axis) with the volume of strong base titrated against its (x-axis)?

  • A. I
  • B. II
  • C. III
  • D. IV

11. Which of the graphs illustrates the variation of the solubility of a salt in water (y-axis), with an increase in temperature (x-axis) if the dissolution process is exothermic?

  • A. I
  • B. II
  • C. III
  • D. IV

12. The formation of ethene from dehydration of ethanol can be described as——-

  • A. an addition reaction
  • B. an elimination reaction
  • C. an oxidation reaction
  • D. a substitution reaction

13. Which of the following gasses is highly soluble in water at room temperature

  • A. ammonia
  • B. carbon (IV) oxide
  • C. chlorine
  • D. nitrogen

14. A molecular of phosphorus is

  • A. diatomic
  • B. triatomic
  • C. tetra atomic
  • D. monoatomic

15. The most common method of preparing insoluble salts is by

  • A. filtration
  • B. decomposition
  • C. neutralization
  • D. double decomposition
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