WAEC 2026 Chemistry OBJ & Essay Questions and Answers (May/June)

WAEC 2026 Chemistry Questions and Answers – May/June

Preparing for the WAEC 2026 Chemistry examination requires a solid understanding of key concepts, practical applications, and past question patterns. This guide provides likely objective and essay questions with accurate answers to help candidates revise effectively and boost their chances of success in the May/June exam.

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WAEC 2026 Chemistry Questions and Answers – May/June SECTION A: OBJECTIVE QUESTIONS (1–20)

Choose the correct option from A–D

1. The smallest unit of an element that retains its properties is
   A. Molecule
   B. Atom
   C. Ion
   D. Compound
   Answer: B
2. The pH of a neutral solution at 25°C is
   A. 0
   B. 14
   C. 7
   D. 10
   Answer: C
3. Which of the following is an alkali?
   A. NaCl
   B. HCl
   C. NaOH
   D. CO₂
   Answer: C
4. The process of converting solid directly to gas is called
   A. Evaporation
   B. Sublimation
   C. Condensation
   D. Freezing
   Answer: B
5. Which gas is evolved when zinc reacts with dilute hydrochloric acid?
   A. Oxygen
   B. Hydrogen
   C. Nitrogen
   D. Carbon dioxide
   Answer: B
6. The oxidation state of oxygen in H₂O is
   A. +1
   B. -1
   C. -2
   D. +2
   Answer: C
7. Avogadro’s number is
   A. 6.02 × 10²³
   B. 3.00 × 10⁸
   C. 1.60 × 10⁻¹⁹
   D. 9.81
   Answer: A
8. Which of the following is a covalent compound?
   A. NaCl
   B. CaO
   C. CH₄
   D. KBr
   Answer: C
9. The main component of natural gas is
   A. Ethane
   B. Methane
   C. Propane
   D. Butane
   Answer: B
10. Which of the following metals is most reactive?
    A. Copper
    B. Zinc
    C. Potassium
    D. Iron
    Answer: C
11. The functional group in alcohol is
    A. -COOH
    B. -OH
    C. -NH₂
    D. -CHO
    Answer: B
12. Electrolysis of water produces
    A. Hydrogen and Oxygen
    B. Nitrogen and Oxygen
    C. Hydrogen and Nitrogen
    D. Carbon dioxide and Oxygen
    Answer: A
13. The SI unit of concentration is
    A. mol/dm³
    B. g/cm³
    C. kg
    D. m/s
    Answer: A
14. Which of the following is a noble gas?
    A. Oxygen
    B. Nitrogen
    C. Neon
    D. Hydrogen
    Answer: C
15. The boiling point of water is
    A. 0°C
    B. 50°C
    C. 100°C
    D. 150°C
    Answer: C
16. An isotope differs in
    A. Atomic number
    B. Mass number
    C. Chemical properties
    D. Valency
    Answer: B
17. Which compound turns blue litmus red?
    A. Base
    B. Acid
    C. Salt
    D. Alkali
    Answer: B
18. Rusting of iron requires
    A. Oxygen only
    B. Water only
    C. Air and water
    D. Hydrogen
    Answer: C
19. Which process is used to separate crude oil?
    A. Filtration
    B. Fractional distillation
    C. Evaporation
    D. Chromatography
    Answer: B
20. The bond in NaCl is
    A. Covalent
    B. Metallic
    C. Ionic
    D. Hydrogen
    Answer: C

WAEC 2026 Chemistry Questions and Answers – May/June SECTION B: ESSAY QUESTIONS AND ANSWERS (1–20)

1. Define an atom and a molecule.

Answer:
An atom is the smallest particle of an element that retains its chemical properties. A molecule is the smallest unit of a compound or element that can exist independently.

2. Explain the kinetic theory of matter.

Answer:
It states that matter is made up of tiny particles in constant motion. The movement increases with temperature.

3. State three differences between acids and bases.

Answer:

• Acids turn blue litmus red; bases turn red litmus blue.
• Acids release H⁺ ions; bases release OH⁻ ions.
• Acids have pH < 7; bases have pH > 7.

4. What is electrolysis?

Answer:
Electrolysis is the chemical decomposition of a compound using electric current.

5. Define molar mass.

Answer:
The mass of one mole of a substance expressed in grams per mole (g/mol).

6. Explain the term oxidation.

Answer:
Oxidation is the loss of electrons or addition of oxygen.

7. What is a catalyst?

Answer:
A catalyst is a substance that increases the rate of a chemical reaction without being consumed.

8. State the law of conservation of mass.

Answer:
Mass is neither created nor destroyed in a chemical reaction.

9. What are isotopes?

Answer:
Atoms of the same element with the same atomic number but different mass numbers.

10. Define solubility.

Answer:
The maximum amount of solute that can dissolve in a solvent at a given temperature.

11. Explain covalent bonding.

Answer:
A bond formed by sharing electrons between atoms.

12. What is an electrolyte?

Answer:
A substance that conducts electricity in solution or molten state.

13. List three uses of acids.

Answer:

• Battery production
• Food preservation
• Manufacturing fertilizers

14. Define pH scale.

Answer:
A scale used to measure acidity or alkalinity from 0 to 14.

15. What is an element?

Answer:
A pure substance made of only one type of atom.

16. Explain the term compound.

Answer:
A substance formed by the chemical combination of two or more elements.

17. State three properties of metals.

Answer:

• Good conductors of heat
• Malleable
• Ductile

18. What is rusting?

Answer:
The corrosion of iron due to reaction with oxygen and water.

19. Define organic chemistry.

Answer:
The study of carbon-containing compounds.

20. List two factors affecting reaction rate.

Answer:

• Temperature
• Concentration

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