WAEC Chemistry 2022 past questions

Checked by the Skolra question team · Last updated 15 October 2026

Ten questions from the 2022 WAEC Chemistry paper, with answers and explanations. We hold 49 questions from this paper, and the Skolra app has all of them.

WAEC Chemistry 2022 questions and answers

1. 1.

   Which of the following bond types is intermolecular?

   1. A
      Metallic bond
   2. B
      Hydrogen bond
      Correct
   3. C
      Covalent bond
   4. D
      Ionic bond
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   Answer: B

   Intermolecular forces act between separate molecules rather than within them. Hydrogen bonds form between molecules containing hydrogen bonded to a highly electronegative atom (F, O, or N). Covalent, ionic, and metallic bonds are all intramolecular or lattice-holding forces, not intermolecular.

2. 2.

   A hydrogen chloride gas reacted with oxygen gas to yield water and chlorine gas. The mole ratio of the hydrogen chloride gas to water is

   1. A
      2:1
      Correct
   2. B
      1:2
   3. C
      1:1
   4. D
      3:1
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   Answer: A

   The balanced equation is 4HCl + O₂ → 2H₂O + 2Cl₂. From this stoichiometry, 4 moles of HCl produce 2 moles of water. Therefore the mole ratio of HCl to H₂O = 4:2 = 2:1.

3. 3.

   The cleansing effect of soap is low in acidic water because of

   1. A
      increased pH of the water
   2. B
      formation of insoluble fatty acids
      Correct
   3. C
      increased ionization of soap molecules
   4. D
      formation of sodium hydroxide
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   Answer: B

   Soap consists of sodium salts of fatty acids (RCOO⁻Na⁺). In acidic water, H⁺ ions react with the carboxylate group: RCOO⁻ + H⁺ → RCOOH. The resulting fatty acid is insoluble and cannot form micelles, so the soap loses its ability to emulsify grease and clean effectively.

4. 4.

   A colourless gas with a pungent smell is evolved when dilute hydrochloric acid is added to a sample of a salt. The gas evolved could turn

   1. A
      moist blue litmus paper red
      Correct
   2. B
      anhydrous copper(II) sulfate blue
   3. C
      moist red litmus paper blue
   4. D
      starch-iodide paper blue
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   Answer: A

   A colourless pungent gas produced when dilute HCl acts on a salt is likely SO₂ (from a sulfite) or H₂S (from a sulfide). Both gases are acidic and will turn moist blue litmus paper red. Only a basic gas such as NH₃ would turn red litmus blue; neither SO₂ nor H₂S would do so.

5. 5.

   Which of the following properties indicate that an element is a metal. It

   
   I. reacts with oxygen to form an acidic oxide
   II. forms ionic chlorides
   III. has variable oxidation states
   IV. displaces hydrogen from dilute HCl

   1. A
      I, II and III only
   2. B
      II and IV only
      Correct
   3. C
      I and III only
   4. D
      II, III and IV only
   Show answerHide answer

   Answer: B

   Metals form ionic (not acidic) chlorides by losing electrons (property II). Metals displace hydrogen from dilute acids like HCl because they are more reactive than hydrogen (property IV). Property I is false—metals form basic oxides, not acidic ones. Property III applies only to transition metals, not metals in general.
6. 6.

   Alkanols can be manufactured from alkenes by the initial reaction of alkenes with

   1. A
      dilute hydrochloric acid
   2. B
      sodium hydroxide
   3. C
      concentrated sulfuric acid
      Correct
   4. D
      potassium permanganate
   Show answerHide answer

   Answer: C

   In the indirect hydration process, alkenes first react with concentrated H₂SO₄ to form alkyl hydrogen sulfate (e.g., C₂H₄ + H₂SO₄ → C₂H₅HSO₄). Subsequent hydrolysis with water yields the alkanol (C₂H₅OH) and regenerates the acid. Concentrated sulfuric acid is thus the initial reagent.

7. 7.

   Which of the following statements about atoms of a metal is correct? They

   1. A
      Have their number of neutrons always equal to their number of electrons
   2. B
      Easily lose electrons in their outermost shell to form positive ions
      Correct
   3. C
      Easily gain electrons in their outermost shell to form negative ions
   4. D
      Always have more protons than electrons in the neutral state
   Show answerHide answer

   Answer: B

   Metal atoms have few loosely-held electrons in the outermost shell, making it easy to lose them and form cations. This low ionization energy is the defining property distinguishing metals from non-metals. For example, sodium readily loses one electron to form Na+. A neutral atom always has equal protons and electrons; only ionized atoms differ.
8. 8.

   The electron configuration of carbon atom in its excited state is

   1. A
      1s2 2p3 3s1
   2. B
      1s2 2s2 2p4
   3. C
      1s2 2s2 2p2
   4. D
      1s2 2s1 2p3
      Correct
   Show answerHide answer

   Answer: D

   Carbon's ground state configuration is 1s2 2s2 2p2 with only two unpaired electrons. In the excited state, one 2s electron is promoted to 2p orbital, yielding 1s2 2s1 2p3 with four unpaired electrons. This excited configuration enables sp3 hybridization and formation of four covalent bonds in molecules like CH4.
9. 9.

   Charcoal is used in the decolourization of sugar because of its

   1. A
      Adsorptive property
      Correct
   2. B
      Catalytic property
   3. C
      Bleaching action
   4. D
      Oxidizing property
   Show answerHide answer

   Answer: A

   Charcoal is highly porous with enormous surface area that physically adsorbs colored impurities from sugar solutions without chemical reaction. The impurities stick to the charcoal surface and are removed by filtration. Unlike bleaching agents that chemically destroy color through oxidation, charcoal simply traps particles on its surface through physical adsorption.
10. 10.

    Ionization energy increases across the period in the periodic table because

    1. A
       The number of electron shells increases, so outer electrons are shielded more from the nucleus
    2. B
       The atomic radius increases while the number of electron shells stays the same, weakening the pull on outer electrons
    3. C
       The elements become more metallic, so electrons are lost more easily
    4. D
       The nuclear charge increases while the shielding effect stays roughly constant, so the outer electrons are held more tightly
       Correct
    Show answerHide answer

    Answer: D

    Across a period, electrons are added to the same shell, so shielding remains roughly constant. Meanwhile, nuclear charge increases as protons are added. The result is that atomic radius shrinks and outer electrons are held more tightly, requiring more energy for removal, thus increasing ionization energy progressively from left to right.

The questions come from past JAMB, WAEC and NECO papers. We use software to help write the answer options and explanations, and every answer is checked twice before it goes on the site. How we check

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Practise all 49 questions we hold from the 2022 paper, on a timed CBT screen

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