Preparing for the 2026 NECO Chemistry examination? If you are searching for 2026 NECO Chemistry Objective and Essay Questions and Answers, verified NECO Chemistry expo, or today’s NECO Chemistry theory and objective solutions, you are in the right place.
This guide provides timely updates, exam tips, and educational support to help candidates prepare effectively for the 2026 NECO Chemistry paper. You will also learn the exam format, the types of objective and essay questions to expect, important topics to revise, and practical strategies for answering questions accurately within the allotted time.
Chemistry remains one of the most important science subjects in the NECO Senior School Certificate Examination (SSCE). A strong performance can improve your overall results and increase your chances of gaining admission into universities, polytechnics, colleges of education, and other higher institutions in Nigeria.
Whether you are writing the examination for the first time or retaking the subject to improve your grades, this comprehensive guide will help you prepare with confidence. Read to the end for the latest updates, revision tips, and everything you need to maximize your performance in the 2026 NECO Chemistry Objective and Essay examination.
CHEMISTRY
PAPER I – OBJECTIVE TEST (PART 1)
Time Allowed: 1 Hour 30 Minutes
Note: This is an original practice paper designed to reflect the current NECO Chemistry syllabus and examination style. It is not an official or leaked 2026 examination paper. The questions cover core syllabus areas such as atomic structure, stoichiometry, periodic chemistry, acids and bases, organic chemistry, and electrochemistry.
INSTRUCTIONS TO CANDIDATES
- Answer Questions 1–30.
- Each question is followed by four options (A–D).
- Choose the most appropriate answer.
- Each question carries 1 mark.
QUESTIONS 1–60
1. The smallest particle of an element that retains its chemical properties is the
A. Molecule
B. Ion
C. Atom
D. Electron
Answer: C
2. The atomic number of an element is equal to the number of
A. Neutrons only
B. Electrons only
C. Protons
D. Nucleons
Answer: C
3. Isotopes of an element have the same
A. Mass number
B. Number of neutrons
C. Atomic number
D. Relative molecular mass
Answer: C
4. Which particle has no electrical charge?
A. Electron
B. Proton
C. Neutron
D. Positron
Answer: C
5. The maximum number of electrons in the second shell is
A. 2
B. 8
C. 18
D. 32
Answer: B
6. Sodium belongs to Group
A. I
B. II
C. VII
D. VIII
Answer: A
7. Chlorine belongs to
A. Noble gases
B. Halogens
C. Alkali metals
D. Transition metals
Answer: B
8. The most reactive non-metal is
A. Oxygen
B. Chlorine
C. Fluorine
D. Nitrogen
Answer: C
9. Electrovalent bonding involves
A. Sharing of electrons
B. Transfer of electrons
C. Sharing of protons
D. Transfer of neutrons
Answer: B
10. Methane (CH₄) contains
A. Ionic bonds only
B. Metallic bonds
C. Covalent bonds
D. Hydrogen bonds
Answer: C
11. Which compound is ionic?
A. H₂O
B. CO₂
C. NaCl
D. NH₃
Answer: C
12. Diamond is a giant
A. Ionic crystal
B. Metallic lattice
C. Covalent structure
D. Molecular crystal
Answer: C
2026 NECO Chemistry Objective and Essay Questions and Answers
13. One mole contains
A. 6.02 × 10²³ particles
B. 6.02 × 10²² particles
C. 3.01 × 10²³ particles
D. 1.00 × 10²³ particles
Answer: A
14. The relative molecular mass of H₂SO₄ is
A. 96
B. 98
C. 100
D. 102
Answer: B
15. Which law states that matter is neither created nor destroyed during a chemical reaction?
A. Boyle’s law
B. Charles’ law
C. Law of Conservation of Mass
D. Avogadro’s law
Answer: C
16. Diffusion is fastest in
A. Solids
B. Liquids
C. Gases
D. Plasma only
Answer: C
17. Increasing temperature generally causes gas molecules to
A. Move more slowly
B. Stop moving
C. Move faster
D. Become liquids
Answer: C
Acids, Bases and Salts
18. Which of the following is an acid?
A. NaOH
B. NH₄OH
C. HCl
D. KOH
Answer: C
19. Blue litmus turns red in
A. Alkalis
B. Acids
C. Salts
D. Water
Answer: B
20. The pH of a neutral solution is
A. 1
B. 5
C. 7
D. 14
Answer: C
21. Neutralization produces
A. Acid only
B. Alkali only
C. Salt and water
D. Hydrogen only
Answer: C
Organic Chemistry
22. The simplest hydrocarbon is
A. Ethane
B. Methane
C. Propane
D. Butane
Answer: B
23. Ethene belongs to the
A. Alkanes
B. Alkenes
C. Alkynes
D. Alcohols
Answer: B
24. Fermentation of sugar produces
A. Ethanol
B. Methane
C. Benzene
D. Ethanoic acid
Answer: A
2026 NECO Chemistry Objective and Essay Questions and Answers
25. Oxidation involves
A. Gain of electrons
B. Loss of electrons
C. Gain of neutrons
D. Loss of protons
Answer: B
26. Reduction is
A. Gain of electrons
B. Gain of oxygen
C. Loss of hydrogen
D. Increase in oxidation number
Answer: A
27. Electrolysis requires
A. Heat only
B. Electric current
C. Sunlight only
D. Pressure
Answer: B
28. The major constituent of natural gas is
A. Propane
B. Butane
C. Methane
D. Ethene
Answer: C
29. Acid rain is mainly caused by
A. Carbon dioxide and nitrogen
B. Sulfur dioxide and nitrogen oxides
C. Oxygen and hydrogen
D. Chlorine gas
Answer: B
30. A catalyst
A. Is consumed during a reaction
B. Slows every reaction
C. Increases the rate of reaction without being permanently changed
D. Changes the products formed
Answer: C
31. Boyle’s law states that for a fixed mass of gas at constant temperature, the pressure is
A. Directly proportional to the volume
B. Inversely proportional to the volume
C. Equal to the volume
D. Independent of the volume
Answer: B
32. Charles’ law states that the volume of a fixed mass of gas is directly proportional to its absolute temperature at constant
A. Mass
B. Pressure
C. Density
D. Humidity
Answer: B
33. Which instrument is commonly used to measure atmospheric pressure?
A. Hydrometer
B. Thermometer
C. Barometer
D. Hygrometer
Answer: C
2026 NECO Chemistry Objective and Essay Questions and Answers
34. Which of the following factors generally increases the rate of a chemical reaction?
A. Lower temperature
B. Smaller surface area
C. Presence of a catalyst
D. Lower concentration of reactants
Answer: C
35. A catalyst functions by
A. Increasing the activation energy
B. Decreasing the activation energy
C. Being completely used up during the reaction
D. Changing the products formed
Answer: B
36. An exothermic reaction
A. Absorbs heat from the surroundings
B. Releases heat to the surroundings
C. Occurs only in gases
D. Cannot be reversed
Answer: B
37. Which process is endothermic?
A. Freezing of water
B. Condensation
C. Melting of ice
D. Neutralization
Answer: C
38. Chemical equilibrium is established when
A. Reactants are completely consumed
B. Forward and reverse reactions occur at equal rates
C. The reaction stops completely
D. Products are removed continuously
Answer: B
39. Increasing the concentration of reactants generally shifts the equilibrium toward
A. Reactants
B. Products
C. Neither side
D. The catalyst
Answer: B
40. The solubility of most solid substances in water generally
A. Decreases with increasing temperature
B. Increases with increasing temperature
C. Remains constant
D. Becomes zero
Answer: B
2026 NECO Chemistry Objective and Essay Questions and Answers
41. Blue litmus paper turns red in the presence of
A. Alkalis
B. Acids
C. Salts
D. Neutral solutions
Answer: B
42. Which reagent is commonly used to test for chloride ions?
A. Sodium hydroxide solution
B. Silver nitrate solution
C. Dilute hydrochloric acid
D. Bromine water
Answer: B
43. A white precipitate with silver nitrate indicates the possible presence of
A. Sulfate ions
B. Chloride ions
C. Carbonate ions
D. Nitrate ions
Answer: B
44. Carbon dioxide gas turns ______ milky.
A. Limewater
B. Bromine water
C. Distilled water
D. Ethanol
Answer: A
45. During electrolysis, oxidation occurs at the
A. Cathode
B. Anode
C. Salt bridge
D. Electrolyte only
Answer: B
46. Reduction takes place at the
A. Anode
B. Cathode
C. Positive terminal only
D. Electrolyte
Answer: B
47. The extraction of aluminium is carried out mainly by
A. Distillation
B. Electrolysis
C. Filtration
D. Sublimation
Answer: B
48. Rusting of iron requires
A. Nitrogen only
B. Oxygen and water
C. Carbon dioxide only
D. Hydrogen only
Answer: B
49. The functional group present in alcohols is
A. –COOH
B. –OH
C. –CHO
D. –NH₂
Answer: B
50. Ethanoic acid belongs to the family of
A. Alcohols
B. Esters
C. Carboxylic acids
D. Ketones
Answer: C
51. Unsaturated hydrocarbons contain at least one
A. Ionic bond
B. Double or triple carbon-carbon bond
C. Metallic bond
D. Hydrogen bond
Answer: B
52. The addition of hydrogen to an unsaturated compound is known as
A. Polymerization
B. Hydrogenation
C. Fermentation
D. Cracking
Answer: B
53. Which gas contributes most to the greenhouse effect?
A. Hydrogen
B. Carbon dioxide
C. Nitrogen
D. Helium
Answer: B
54. Ozone in the stratosphere is important because it
A. Produces rainfall
B. Absorbs harmful ultraviolet radiation
C. Causes acid rain
D. Increases air pollution
Answer: B
55. Water hardness caused by calcium hydrogen carbonate is known as
A. Permanent hardness
B. Temporary hardness
C. Saline hardness
D. Industrial hardness
Answer: B
56. Which method removes temporary hardness from water?
A. Boiling
B. Filtration
C. Distillation
D. Sedimentation
Answer: A
57. The relative molecular mass (Mr) of CO₂ is
A. 40
B. 42
C. 44
D. 46
Answer: C
58. One mole of oxygen molecules (O₂) contains
A. 6.02×10236.02 \times 10^{23}6.02×1023 molecules
B. 3.01×10233.01 \times 10^{23}3.01×1023 molecules
C. 1.00×10231.00 \times 10^{23}1.00×1023 molecules
D. 12.04×102312.04 \times 10^{23}12.04×1023 molecules
Answer: A
59. The oxidation number of oxygen in most compounds is
A. +2
B. –2
C. +1
D. 0
Answer: B
60. Which of the following is an example of a chemical change?
A. Melting of ice
B. Dissolving sugar in water
C. Burning of magnesium ribbon
D. Breaking a glass bottle
Answer: C
CHEMISTRY
PAPER II – ESSAY (PROPOSED PRACTICE PAPER)
Time Allowed: 2 Hours 30 Minutes
Maximum Marks: 100
Note: This is an original practice paper designed to reflect the NECO Chemistry syllabus and examination style. It is intended for revision and is not an official or leaked 2026 examination paper.
INSTRUCTIONS TO CANDIDATES
- Answer Five (5) questions only.
- Question 1 is compulsory.
- All questions carry 20 marks.
- Where necessary, write balanced chemical equations.
- Show all calculations clearly.
- Credit will be given for correct chemical symbols, units, and logical presentation.
QUESTION 1 (COMPULSORY)
(a) Define the following:
i. Atom
ii. Molecule
iii. Mole
iv. Ion
(b) State the differences between:
i. Physical change and Chemical change
ii. Element and Compound
(c) State four physical properties and four chemical properties of matter.
MODEL ANSWER
(a)
Atom
The smallest particle of an element that retains its chemical properties.
Molecule
The smallest particle of a substance capable of independent existence and consisting of two or more atoms chemically combined.
Mole
The amount of substance containing 6.02 × 10²³ particles (Avogadro’s constant).
Ion
An atom or group of atoms carrying a positive or negative electrical charge due to the loss or gain of electrons.
(b)
Physical Change
- No new substance is formed.
- Usually reversible.
- Only physical properties change.
Chemical Change
- New substances are formed.
- Usually irreversible.
- Chemical composition changes.
Element
A pure substance made up of only one type of atom.
Compound
A substance formed when two or more elements combine chemically in fixed proportions.
(c)
Physical Properties
- Density
- Melting point
- Boiling point
- Colour
Chemical Properties
- Combustibility
- Reactivity with acids
- Oxidation
- Corrosion
2026 NECO Chemistry Objective and Essay Questions and Answers
QUESTION 2
(a) Explain the Periodic Table.
(b) State five characteristics of Group I (Alkali Metals).
(c) State five characteristics of Group VII (Halogens).
MODEL ANSWER
Periodic Table
The Periodic Table is an arrangement of elements in order of increasing atomic number, showing recurring patterns in their chemical and physical properties.
Characteristics of Group I
- One valence electron.
- Very reactive metals.
- Form positive ions (+1).
- React vigorously with water.
- Soft and have relatively low melting points.
Characteristics of Group VII
- Seven valence electrons.
- Highly reactive non-metals.
- Form negative ions (–1).
- Exist as diatomic molecules.
- React with metals to form salts.
QUESTION 3
(a) State Boyle’s Law.
(b) State Charles’ Law.
(c) A gas occupies 240 cm³ at 300 K. Calculate its volume at 450 K if the pressure remains constant.
MODEL ANSWER
Boyle’s Law
For a fixed mass of gas at constant temperature, the pressure is inversely proportional to its volume.
Charles’ Law
For a fixed mass of gas at constant pressure, the volume is directly proportional to its absolute temperature.
Calculation
Given:
- V₁ = 240 cm³
- T₁ = 300 K
- T₂ = 450 K
Using Charles’ Law:
V1T1=V2T2\frac{V_1}{T_1}=\frac{V_2}{T_2}T1V1=T2V2 V2=240×450300V_2=\frac{240\times450}{300}V2=300240×450 V2=360 cm3V_2=360\ \text{cm}^3V2=360 cm3
Answer: 360 cm³
QUESTION 4
(a) Explain Electrolysis.
(b) Differentiate between:
i. Electrolyte
ii. Electrode
iii. Electrolytic Cell
(c) State four applications of electrolysis.
MODEL ANSWER
Electrolysis
Electrolysis is the chemical decomposition of an electrolyte by passing an electric current through its molten or aqueous solution.
Differences
Electrolyte
A substance that conducts electricity when molten or dissolved in water because it contains mobile ions.
Electrode
A conductor through which electric current enters or leaves the electrolyte.
Electrolytic Cell
The apparatus in which electrolysis takes place.
Applications
- Electroplating.
- Purification of copper.
- Extraction of aluminium.
- Manufacture of chlorine and sodium hydroxide.
QUESTION 5
(a) Explain the following terms:
i. Acid
ii. Base
iii. Alkali
iv. Salt
(b) Describe three laboratory methods of preparing salts.
MODEL ANSWER
Definitions
Acid
A substance that produces hydrogen ions (H⁺) in aqueous solution.
Base
A substance that reacts with an acid to form salt and water.
Alkali
A soluble base that produces hydroxide ions (OH⁻) in water.
Salt
An ionic compound formed when the hydrogen ion of an acid is replaced by a metal or ammonium ion.
Preparation of Salts
1. Neutralization
Acid + Alkali → Salt + Water
Example:
HCl + NaOH → NaCl + H₂O
2. Reaction of Acid with Metal
Zn + H₂SO₄ → ZnSO₄ + H₂
3. Reaction of Acid with Carbonate
CaCO₃ + 2HCl → CaCl₂ + CO₂ + H₂O
QUESTION 6
(a) Explain the following:
i. Hydrocarbons
ii. Homologous Series
iii. Functional Group
(b) Differentiate between Alkanes and Alkenes.
(c) State three uses each of Ethanol and Ethanoic Acid.
2026 NECO Chemistry Objective and Essay Questions and Answers
MODEL ANSWER
Definitions
Hydrocarbons
Compounds containing only carbon and hydrogen atoms.
Homologous Series
A family of organic compounds with the same functional group and general formula, where successive members differ by a –CH₂– unit.
Functional Group
The atom or group of atoms responsible for the characteristic chemical reactions of an organic compound.
Differences
| Alkanes | Alkenes |
|---|---|
| Saturated hydrocarbons | Unsaturated hydrocarbons |
| Only single C–C bonds | At least one C=C double bond |
| General formula: CₙH₂ₙ₊₂ | General formula: CₙH₂ₙ |
Uses of Ethanol
- Solvent in laboratories and industries.
- Fuel or fuel additive (bioethanol).
- Ingredient in pharmaceuticals and sanitizers.
Uses of Ethanoic Acid
- Manufacture of vinegar.
- Food preservation.
- Production of chemicals such as esters and plastics.
QUESTION 7
(a) Explain corrosion.
(b) State five methods of preventing rusting.
(c) Explain the effects of environmental pollution caused by chemical substances.
MODEL ANSWER
Corrosion
Corrosion is the gradual deterioration of metals due to chemical or electrochemical reactions with their environment. Rusting is the corrosion of iron in the presence of oxygen and moisture.
Methods of Preventing Rusting
- Painting.
- Greasing or oiling.
- Galvanizing (coating with zinc).
- Electroplating.
- Alloying (e.g., stainless steel).
Effects of Chemical Pollution
- Air pollution leading to respiratory diseases.
- Water pollution affecting aquatic life.
- Soil contamination reducing agricultural productivity.
- Acid rain damaging vegetation and buildings.
- Global warming due to greenhouse gas emissions.
- Destruction of the ozone layer by certain chemicals.
- Harm to wildlife and ecosystems through toxic substances.
SUGGESTED MARKING SCHEME
| Question | Marks |
|---|---|
| Question 1 | 20 |
| Question 2 | 20 |
| Question 3 | 20 |
| Question 4 | 20 |
| Question 5 | 20 |
| Question 6 | 20 |
| Question 7 | 20 |
General Mark Allocation (Per Question)
| Component | Marks |
|---|---|
| Definitions/Introduction | 2 |
| Main Explanations | 10 |
| Balanced Equations, Calculations, or Diagrams | 4 |
| Organization, Accuracy, and Correct Chemical Terminology | 4 |
Conclusion
Success in the 2026 NECO Chemistry examination depends on proper preparation, consistent practice, and a solid understanding of the syllabus. Rather than relying on rumors or unverified information, focus on studying past questions, mastering key Chemistry concepts, and managing your time effectively during the examination.
Keep checking this page for the latest updates on the 2026 NECO Chemistry Objective and Essay Questions and Answers, exam tips, and important announcements. If you found this guide helpful, share it with your classmates and bookmark the page so you never miss new information before the examination.
We wish every NECO candidate the very best and hope you achieve outstanding results in your 2026 Chemistry examination.
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