100 Current JAMB Past Questions and Answers on Chemistry for 2025/2026
100 Current JAMB Past Questions and Answers on Chemistry for 2025/2026
JAMB Chemistry Practice Questions and Answers (2025/2026)
1–20: General Chemistry
-
What is the chemical formula for water?
A) H₂O
B) CO₂
C) NaCl
D) HCl
Answer: A) H₂O -
Which of the following elements is a noble gas?
A) Oxygen
B) Nitrogen
C) Helium
D) Carbon
Answer: C) Helium -
What is the pH value of a neutral solution?
A) 7
B) 1
C) 14
D) 0
Answer: A) 7 -
Which of the following is an example of a physical change?
A) Burning wood
B) Rusting of iron
C) Boiling water
D) Digesting food
Answer: C) Boiling water -
What is the chemical symbol for gold?
A) Ag
B) Au
C) Fe
D) Hg
Answer: B) Au -
What is the process of converting a solid directly into a gas called?
A) Melting
B) Freezing
C) Condensation
D) Sublimation
Answer: D) Sublimation -
Which of the following is a diatomic molecule?
A) O₂
B) CO₂
C) H₂O
D) NH₃
Answer: A) O₂ -
What is the atomic number of carbon?
A) 6
B) 12
C) 14
D) 8
Answer: A) 6 -
Which of the following is an alkali metal?
A) Calcium
B) Sodium
C) Aluminum
D) Iron
Answer: B) Sodium -
What is the molar mass of water (H₂O)?
A) 16 g/mol
B) 18 g/mol
C) 20 g/mol
D) 22 g/mol
Answer: B) 18 g/mol -
Which gas is used in the Haber process for ammonia production?
A) Oxygen
B) Nitrogen
C) Carbon dioxide
D) Hydrogen
Answer: B) Nitrogen -
What is the main component of natural gas?
A) Ethane
B) Methane
C) Propane
D) Butane
Answer: B) Methane -
Which of the following is a strong acid?
A) HCl
B) CH₃COOH
C) H₂CO₃
D) HCN
Answer: A) HCl -
What is the oxidation state of sulfur in H₂SO₄?
A) +2
B) +4
C) +6
D) -2
Answer: C) +6 -
Which of the following compounds is an ester?
A) CH₃COOH
B) CH₃CH₂OH
C) CH₃COOCH₃
D) CH₃NH₂
Answer: C) CH₃COOCH₃ -
What is the IUPAC name for CH₄?
A) Methane
B) Ethane
C) Propane
D) Butane
Answer: A) Methane -
Which of the following is a greenhouse gas?
A) Nitrogen
B) Oxygen
C) Carbon dioxide
D) Helium
Answer: C) Carbon dioxide -
What is the color of phenolphthalein in a basic solution?
A) Colorless
B) Pink
C) Red
D) Blue
Answer: B) Pink -
Which of the following metals can displace hydrogen from dilute acids?
A) Copper
B) Silver
C) Zinc
D) Gold
Answer: C) Zinc -
What type of bond is present in NaCl?
A) Covalent bond
B) Ionic bond
C) Metallic bond
D) Hydrogen bond
Answer: B) Ionic bond
100 Current JAMB Past Questions and Answers on Chemistry for 2025/2026
21–40: Atomic Structure & Periodic Table
-
What is the mass number of an atom with 11 protons and 12 neutrons?
A) 12
B) 23
C) 22
D) 11
Answer: B) 23 -
Which of these elements has the smallest atomic radius?
A) Na
B) Mg
C) Al
D) Cl
Answer: D) Cl -
The number of electrons in a neutral atom of oxygen is ____.
A) 6
B) 8
C) 10
D) 12
Answer: B) 8 -
Which group does neon belong to in the periodic table?
A) Group I
B) Group IV
C) Group VIII
D) Group VII
Answer: C) Group VIII -
Isotopes differ in ____.
A) Atomic number
B) Electron number
C) Mass number
D) Chemical properties
Answer: C) Mass number -
Which of the following is the most reactive non-metal?
A) Nitrogen
B) Fluorine
C) Oxygen
D) Sulfur
Answer: B) Fluorine -
Which of the following particles has the least mass?
A) Proton
B) Neutron
C) Electron
D) Nucleus
Answer: C) Electron -
The atomic number of an element is equal to the number of ____.
A) Neutrons
B) Nucleons
C) Protons
D) Electrons and neutrons
Answer: C) Protons -
Which of the following elements has the highest electronegativity?
A) Chlorine
B) Oxygen
C) Nitrogen
D) Fluorine
Answer: D) Fluorine -
Which of the following is a transition element?
A) Magnesium
B) Copper
C) Calcium
D) Potassium
Answer: B) Copper -
All isotopes of an element have the same ____.
A) Mass number
B) Number of neutrons
C) Number of protons
D) Atomic mass
Answer: C) Number of protons -
Which of the following elements is most metallic?
A) Sodium
B) Magnesium
C) Aluminium
D) Potassium
Answer: D) Potassium -
Which quantum number describes the shape of an orbital?
A) Principal (n)
B) Azimuthal (l)
C) Magnetic (m)
D) Spin (s)
Answer: B) Azimuthal (l) -
How many electrons can the M shell hold?
A) 8
B) 18
C) 32
D) 2
Answer: B) 18 -
The correct order of filling atomic orbitals is given by the ____.
A) Aufbau principle
B) Pauli exclusion principle
C) Heisenberg principle
D) Bohr model
Answer: A) Aufbau principle -
Which orbital is filled immediately after 3p?
A) 3d
B) 4s
C) 4p
D) 5s
Answer: B) 4s -
The number of valence electrons in sulfur is ____.
A) 4
B) 6
C) 2
D) 8
Answer: B) 6 -
The electron configuration of carbon is ____.
A) 1s² 2s² 2p²
B) 1s² 2s¹ 2p³
C) 1s² 2s² 2p⁴
D) 1s² 2s² 2p⁶
Answer: A) 1s² 2s² 2p² -
Which subatomic particle has no charge?
A) Proton
B) Neutron
C) Electron
D) Positron
Answer: B) Neutron -
The most abundant element in the earth’s crust is ____.
A) Iron
B) Oxygen
C) Silicon
D) Aluminium
Answer: B) Oxygen
100 Current JAMB Past Questions and Answers on Chemistry for 2025/2026
41–60: Organic Chemistry & Hydrocarbons
-
What is the functional group of alcohols?
A) -COOH
B) -CHO
C) -OH
D) -COO-
Answer: C) -OH -
Which of the following is an alkyne?
A) Ethane
B) Ethene
C) Ethyne
D) Propane
Answer: C) Ethyne -
The IUPAC name for CH₃CH₂COOH is ____.
A) Propanoic acid
B) Butanoic acid
C) Ethanoic acid
D) Methanoic acid
Answer: A) Propanoic acid -
What is the product of the complete combustion of hydrocarbons?
A) CO and H₂O
B) CO₂ and H₂O
C) C and H₂O
D) H₂ and CO₂
Answer: B) CO₂ and H₂O -
Alkanes are said to be ____.
A) Unsaturated hydrocarbons
B) Aromatic compounds
C) Saturated hydrocarbons
D) Reactive compounds
Answer: C) Saturated hydrocarbons -
Which of the following is a secondary alcohol?
A) Propan-2-ol
B) Ethanol
C) Methanol
D) Butan-1-ol
Answer: A) Propan-2-ol -
The process of converting starch to ethanol is called ____.
A) Oxidation
B) Esterification
C) Fermentation
D) Polymerization
Answer: C) Fermentation -
Benzene is classified as a(n) ____.
A) Alkane
B) Alkene
C) Aromatic compound
D) Alkyne
Answer: C) Aromatic compound -
Ethene can undergo ____.
A) Substitution reaction
B) Addition reaction
C) Polymerization only
D) Hydrolysis
Answer: B) Addition reaction -
Which of the following is used in making plastics?
A) Ethyne
B) Ethene
C) Propane
D) Methane
Answer: B) Ethene
100 Current JAMB Past Questions and Answers on Chemistry for 2025/2026
61–80: Electrolysis, Acids/Bases, Thermodynamics
-
What is the electrode where reduction occurs called?
A) Cathode
B) Anode
C) Electrolyte
D) Conductor
Answer: A) Cathode -
Electrolysis of brine produces ____.
A) H₂ and O₂
B) Na and Cl
C) NaOH, Cl₂, and H₂
D) NaOH and O₂
Answer: C) NaOH, Cl₂, and H₂ -
A substance that conducts electricity in molten or aqueous form is a(n) ____.
A) Metal
B) Insulator
C) Electrolyte
D) Non-electrolyte
Answer: C) Electrolyte -
An acid turns blue litmus paper ____.
A) Red
B) Green
C) Colorless
D) Yellow
Answer: A) Red -
The pH of a basic solution is ____.
A) Less than 7
B) Equal to 7
C) Greater than 7
D) Cannot be determined
Answer: C) Greater than 7 -
Which of the following is a weak acid?
A) HCl
B) H₂SO₄
C) CH₃COOH
D) HNO₃
Answer: C) CH₃COOH -
Neutralization reaction always produces ____.
A) Acid and water
B) Base and salt
C) Salt and water
D) Water and carbon dioxide
Answer: C) Salt and water -
Which of the following is used to measure enthalpy change?
A) Thermometer
B) Barometer
C) Calorimeter
D) Hydrometer
Answer: C) Calorimeter -
Which of these is an exothermic process?
A) Melting of ice
B) Combustion of methane
C) Evaporation of water
D) Boiling
Answer: B) Combustion of methane -
The unit of enthalpy is ____.
A) J/kg
B) K/mol
C) J/mol
D) °C
Answer: C) J/mol
100 Current JAMB Past Questions and Answers on Chemistry for 2025/2026
81–100: Reaction Kinetics, Industrial Chemistry, Miscellaneous
-
Which factor does not affect the rate of chemical reactions?
A) Temperature
B) Catalyst
C) Surface area
D) Color of the reactants
Answer: D) Color of the reactants -
Catalysts work by ____.
A) Lowering activation energy
B) Increasing activation energy
C) Changing product composition
D) Consuming reactants
Answer: A) Lowering activation energy -
Which industry uses the Contact process?
A) Ammonia production
B) Soap manufacturing
C) Sulphuric acid production
D) Petroleum refining
Answer: C) Sulphuric acid production -
The catalyst used in the Haber process is ____.
A) Iron
B) Platinum
C) Vanadium(V) oxide
D) Nickel
Answer: A) Iron -
What is the major pollutant released from automobile engines?
A) SO₂
B) CO
C) NO
D) CO₂
Answer: B) CO -
What is the raw material for the Solvay process?
A) Limestone
B) Potash
C) Brine and limestone
D) Sulfur
Answer: C) Brine and limestone -
The principal ore of aluminium is ____.
A) Haematite
B) Bauxite
C) Galena
D) Cryolite
Answer: B) Bauxite -
Soap is produced by ____.
A) Fermentation
B) Esterification
C) Saponification
D) Hydrolysis
Answer: C) Saponification -
Which of these is biodegradable?
A) Nylon
B) Polythene
C) Cellulose
D) PVC
Answer: C) Cellulose -
Hard water does not lather easily with soap because it contains ____.
A) Na⁺ and Cl⁻
B) Ca²⁺ and Mg²⁺
C) Fe²⁺ and Fe³⁺
D) CO₃²⁻
Answer: B) Ca²⁺ and Mg²⁺ -
Which of the following will displace copper from CuSO₄ solution?
A) Silver
B) Gold
C) Zinc
D) Mercury
Answer: C) Zinc -
The gas used in fire extinguishers is ____.
A) Oxygen
B) Hydrogen
C) Carbon dioxide
D) Nitrogen
Answer: C) Carbon dioxide -
The bond in an O₂ molecule is ____.
A) Single covalent
B) Double covalent
C) Triple covalent
D) Ionic
Answer: B) Double covalent -
Which of the following is used to test for the presence of starch?
A) Benedict’s solution
B) Biuret reagent
C) Iodine solution
D) Limewater
Answer: C) Iodine solution -
Which gas is released when an acid reacts with a metal carbonate?
A) Oxygen
B) Carbon dioxide
C) Hydrogen
D) Nitrogen
Answer: B) Carbon dioxide -
The common name of NaHCO₃ is ____.
A) Baking soda
B) Table salt
C) Washing soda
D) Caustic soda
Answer: A) Baking soda -
Which of the following is a d-block element?
A) Na
B) Ca
C) Fe
D) C
Answer: C) Fe -
Which acid is used in car batteries?
A) Nitric acid
B) Sulphuric acid
C) Hydrochloric acid
D) Acetic acid
Answer: B) Sulphuric acid -
Which is not a greenhouse gas?
A) Methane
B) Nitrogen
C) Carbon dioxide
D) Water vapour
Answer: B) Nitrogen -
A solution that resists change in pH is called a ____.
A) Catalyst
B) Buffer
C) Titrant
D) Indicator
Answer: B) Buffer -
What color does litmus turn in acid?
A) Blue
B) Green
C) Red
D) Purple
Answer: C) Red -
Which ion is responsible for basicity?
A) H⁺
B) OH⁻
C) Na⁺
D) Cl⁻
Answer: B) OH⁻ -
What is the name of Ca(OH)₂?
A) Calcium oxide
B) Calcium carbonate
C) Calcium hydroxide
D) Calcium sulphate
Answer: C) Calcium hydroxide -
A strong base completely ____.
A) Precipitates
B) Dissociates in water
C) Burns in air
D) Neutralizes weak acids only
Answer: B) Dissociates in water -
The atomic mass of an element is measured in ____.
A) Grams
B) Daltons
C) Moles
D) Newtons
Answer: B) Daltons -
Which of the following processes is used to separate a mixture of salt and sand?
A) Distillation
B) Sublimation
C) Filtration
D) Chromatography
Answer: C) Filtration -
Which of the following is used in water treatment?
A) Sodium chloride
B) Aluminum sulphate
C) Sodium carbonate
D) Sulfur
Answer: B) Aluminum sulphate -
Which gas is responsible for the pungent smell in ammonia solution?
A) H₂S
B) SO₂
C) NH₃
D) CO
Answer: C) NH₃ -
The major constituent of air is ____.
A) Oxygen
B) Carbon dioxide
C) Nitrogen
D) Hydrogen
Answer: C) Nitrogen -
The gas that extinguishes fire and does not support combustion is ____.
A) Nitrogen
B) Carbon dioxide
C) Oxygen
D) Hydrogen
Answer: B) Carbon dioxide -
How many moles of oxygen are in 32g of O₂?
A) 1
B) 2
C) 4
D) 0.5
Answer: A) 1 -
Which of the following is an amphoteric oxide?
A) Na₂O
B) CO₂
C) ZnO
D) SO₂
Answer: C) ZnO -
The molar volume of gas at STP is ____.
A) 11.2 dm³
B) 22.4 dm³
C) 24.0 dm³
D) 28.0 dm³
Answer: B) 22.4 dm³ -
The movement of particles from higher to lower concentration is called ____.
A) Effusion
B) Osmosis
C) Diffusion
D) Sublimation
Answer: C) Diffusion -
A chemical change is usually ____.
A) Reversible
B) Temporary
C) Permanent
D) Physical
Answer: C) Permanent -
Which is not a property of metals?
A) Conductivity
B) Brittleness
C) Ductility
D) Malleability
Answer: B) Brittleness -
The flame used in welding is ____.
A) Yellow flame
B) Blue flame
C) Luminous flame
D) Oxy-acetylene flame
Answer: D) Oxy-acetylene flame -
Which of the following is a natural polymer?
A) Nylon
B) Starch
C) PVC
D) Teflon
Answer: B) Starch -
Which is a characteristic of endothermic reactions?
A) Release of heat
B) Absorption of heat
C) Formation of gas
D) Evolution of light
Answer: B) Absorption of heat -
The process of converting unsaturated oils to saturated fats is called ____.
A) Hydrogenation
B) Esterification
C) Polymerization
D) Oxidation
Answer: A) Hydrogenation