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JAMB2025chemistry
Q1. The gas that turns lime water milky is?
AOxygen
BNitrogen
CCarbon(IV) oxide
DHydrogen
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Q2. Which of the following is a non-metal?
AIron
BCopper
CSulfur
DZinc
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Q3. The process of separating components of crude oil is?
ADistillation
BSublimation
CFractional distillation
DEvaporation
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Q4. What is the IUPAC name of CH3CH2OH?
AMethanol
BEthanol
CPropanol
DEthane
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Q5. Which law states that the volume of a gas is inversely proportional to its pressure at constant temperature?
ABoyle's Law
BCharles' Law
CGay-Lussac's Law
DAvogadro's Law
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JAMB2025chemistry
Q6. An element X has atomic number 11. Which group does it belong to?
A1
B2
C17
D18
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Q7. Which of the following is a dehydrating agent?
AConc. H2SO4
BNaOH
CNaCl
DHCl
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JAMB2025chemistry
Q8. What is the oxidation number of oxygen in H2O2?
A-1
B-2
D+1
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Q9. The presence of impurities in a substance leads to?
AIncrease in melting point
BDecrease in melting point
CIncrease in boiling point
DB and C
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JAMB2025chemistry
Q10. Which element is a noble gas?
ANeon
BNitrogen
CFluorine
DOxygen
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JAMB2025chemistry
Q11. What is the product of the reaction between ethene and hydrogen?
AEthane
BEthanol
CEthyl
DEthyne
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JAMB2025chemistry
Q12. Which of these is a primary cell?
ALeclanche cell
BLead-acid accumulator
CNickel-Cadmium
DAll of the above
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JAMB2025chemistry
Q13. What is the color of phenolphthalein in an acidic medium?
APink
BColorless
CYellow
DBlue
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JAMB2025chemistry
Q14. Calculate the number of moles in 8g of Oxygen gas (O2). (O=16)
A0.25
B0.5
C1
D2
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JAMB2025chemistry
Q15. Which of the following causes permanent hardness in water?
ACa(HCO3)2
BCaCl2
CMgCO3
DNa2CO3
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JAMB2025chemistry
Q16. What is the catalyst used in the contact process?
AV2O5
BFe
CPt
DNi
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JAMB2025chemistry
Q17. Which metal is extracted by electrolysis?
ASodium
BIron
CCopper
DZinc
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JAMB2025chemistry
Q18. The shape of a methane molecule is?
ALinear
BBent
CTetrahedral
DPlanar
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JAMB2025chemistry
Q19. Which of the following is a biodegradable pollutant?
APlastic
BGlass
CPaper
DOil
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JAMB2025chemistry
Q20. How many carbon atoms are in a benzene ring?
A4
B5
C6
D8
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JAMB2025chemistry
Q21. Which radioactive emission has the highest penetrating power?
AAlpha
BBeta
CGamma
DNeutron
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JAMB2025chemistry
Q22. The functional group of carboxylic acids is?
A-OH
B-CHO
C-COOH
D-COOR
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JAMB2025chemistry
Q23. Which of these is used to harden vegetable oil into margarine?
AHydrogen
BNitrogen
COxygen
DChlorine
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JAMB2025chemistry
Q24. The atom of an element is represented by 35/17 X. How many neutrons are in the nucleus?
A17
B18
C35
D52
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JAMB2025chemistry
Q25. Which gas is used in the manufacture of ammonia by the Haber process?
AHydrogen and Nitrogen
BHydrogen and Oxygen
CNitrogen and Oxygen
DHydrogen and Chlorine
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JAMB2025chemistry
Q26. Which of the following salts is acidic?
ANa2CO3
BNaCl
CNH4Cl
DCH3COONa
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JAMB2025chemistry
Q27. What is the hybridization of carbon in ethane (C2H6)?
Asp
Bsp2
Csp3
Ddsp2
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JAMB2025chemistry
Q28. Which component of air is used in light bulbs?
AOxygen
BCarbon(IV) oxide
CArgon
DNitrogen
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JAMB2025chemistry
Q29. The substance used in the preparation of chlorine in the lab is?
AMnO2
BFe2O3
CCuO
DZnO
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JAMB2025chemistry
Q30. Which of these is an example of an endothermic reaction?
ABurning of wood
BPhotosynthesis
CNeutralization
DRespiration
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JAMB2025chemistry
Q31. The IUPAC name of the compound CH3-CH2-CH=CH2 is?
AButane
BBut-1-ene
CBut-2-ene
DButyne
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JAMB2025chemistry
Q32. Which metal is found in chlorophyll?
AIron
BMagnesium
CCalcium
DCopper
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JAMB2025chemistry
Q33. Which gas is responsible for the depletion of the ozone layer?
ASO2
BCFCs
CCO2
DNO2
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JAMB2025chemistry
Q34. What is the name of the reaction between an acid and a base?
ARedox
BEsterification
CNeutralization
DHydrolysis
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JAMB2025chemistry
Q35. The amount of heat evolved during a reaction is measured by?
AThermometer
BCalorimeter
CHydrometer
DBarometer
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JAMB2025chemistry
Q36. Which of the following is a saturated hydrocarbon?
AMethane
BEthene
CEthyne
DBenzene
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JAMB2025chemistry
Q37. What is the oxidation state of Sulfur in SO4^2-?
A+2
B+4
C+6
D-2
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JAMB2025chemistry
Q38. Which of the following is a physical change?
ARusting of iron
BFreezing of water
CBurning of paper
DSourness of milk
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JAMB2025chemistry
Q39. What is the molar volume of a gas at STP?
A11.2 dm3
B22.4 dm3
C44.8 dm3
D10.0 dm3
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JAMB2025chemistry
Q40. Which of these is the hardest natural substance?
AGraphite
BDiamond
CQuartz
DSteel
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jamb2025chemistry
Q41. Which of the following pairs of elements will exhibit diagonal relationship?
ABe and Si
BNa and Be
CLi and Al
DB and Si
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jamb2025chemistry
Q42. The molecule with the highest number of lone pair of electrons is
AH₂O
BNH₃
CCH₄
DCO₂
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jamb2025chemistry
Q43. Carbohydrates can generally be represented by the general formula Cₓ(H₂O)ᵧ. For fructose the value of x is
A3
B12
C5
D6
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jamb2025chemistry
Q44. Which of the following statements is false about hard water?
AHelps animals to build strong teeth
BCannot be supplied in pipes made of lead
CTastes better than soft water
DHelps animals to build strong bones
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jamb2025chemistry
Q45. The property of metal that makes it suitable as a catalyst is
Afilled f-orbital
Bpartially filled d-orbitals
Cpartially filled f-orbital
Dfilled d-orbital
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jamb2025chemistry
Q46. The major product when 2-methylpropene reacts with HCl is
A2-chloro-2-methylpropane
B1-chloro-2-methylpropane
C3-chloro-2-methylpropane
D2-chloro-3-methylbutane
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jamb2025chemistry
Q47. 2X + 2HCl → 2XCl + H₂. In the equation above, X is
AK
BMg
CCa
DBa
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jamb2025chemistry
Q48. The following is not a water pollutant?
Awarm water affluent
Binorganic fertilizers
Coxygen gas
Dbiodegradable waste
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jamb2025chemistry
Q49. In the laboratory preparation of oxygen using potassium trioxochlorate(V), tetraoxomanganate(VII) is usually not recommended in modern laboratory because
Ait forms explosive mixture with carbonaceous materials
Bit is explosive
Cit reacts with the catalyst
Dit is hazardous
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jamb2025chemistry
Q50. The time required to deposit 4.5 g of copper from CuSO₄ solution by passing a current of 2.5 Amperes is (Cu = 64 g; 1F = 96500 C/mol)
A2714 sec
B2527 sec
C5428 sec
D6785 sec
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jamb2025chemistry
Q51. The dusty and sand particles present in the air is an example of
Aa suspension
Ba dispersion
Can emulsion
Da saturated solution
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jamb2025chemistry
Q52. NH₃(g) + HCl(g) → NH₄Cl(g). In the reaction above, increase in pressure will
Alower the equilibrium constant
Bfavour the product
Cfavour the reactant
Dincrease the equilibrium constant
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jamb2025chemistry
Q53. The empirical mass of C₆H₁₂O₆ is [H = 1, C = 12, O = 16]
A90
B180
C45
D30
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jamb2025chemistry
Q54. The acid used in making baking soda and soft drink is
Atartaric acid
Bfatty acid
Cboric acid
Dcitric acid
Correct Answer: D
Citric acid is used as a flavoring and preservative in soft drinks, and reacts with sodium bicarbonate in baking powder to produce CO₂ for leavening. It is the common acid in both applications.
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jamb2025chemistry
Q55. In the table above, the two compounds that will combine in the presence of an acid catalyst to form compound V are
AI and IV
BIII and IV
CI and II
DII and III
Correct Answer: A
Compound V is an ester (RCOOR'). Esters are formed by acid-catalyzed esterification: RCOOH (carboxylic acid = IV) + ROH (alcohol = I) → RCOOR' + H₂O. Therefore compounds I and IV combine to produce compound V.
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jamb2025chemistry
Q56. In the electrolysis of brine using neutral electrodes, which ion is discharged at the anode?
A2H⁺
BNa⁺
CCl⁻
DOH⁻
Correct Answer: C
At the anode, oxidation occurs. Both Cl⁻ and OH⁻ ions are present, but Cl⁻ is selectively discharged due to its higher concentration in brine: 2Cl⁻ → Cl₂ + 2e⁻. Na⁺ and H⁺ are discharged at the cathode, not the anode.
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jamb2025chemistry
Q57. The composition of petroleum varies because it is a
Ahydrocarbon
Bliquid
Cmixture
Dnatural resource
Correct Answer: C
Petroleum is a mixture of many different hydrocarbons with no fixed composition. Because it is a mixture (not a pure substance), its composition varies from one source to another.
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jamb2025chemistry
Q58. Alkenes are represented with the general molecular formula
ACₙH₂ₙ
BCₙH₂ₙ₋₂
CCₙH₂ₙ₊₂
DCₙH₂ₙ₊₁OH
Correct Answer: A
Alkenes contain one C=C double bond and have the general formula CₙH₂ₙ. CₙH₂ₙ₊₂ is for alkanes, CₙH₂ₙ₋₂ is for alkynes, and CₙH₂ₙ₊₁OH is for alkanols.
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Q59. Calculate the pH of 0.001 M KOH solution.
A11
B14
C12
D3
Correct Answer: A
KOH is a strong base: [OH⁻] = 0.001 M = 1 × 10⁻³ M. pOH = -log(10⁻³) = 3. pH = 14 - 3 = 11.
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jamb2025chemistry
Q60. Alkanoic acids have higher boiling points than alkanols because
Aalkanoic acids are more volatile than alkanols
Balkanols are more polar than alkanoic acids
Calkanoic acids are larger molecules
Dalkanoic acids form stronger hydrogen bonds
Correct Answer: D
Alkanoic acids (carboxylic acids) form dimers through two cooperative hydrogen bonds between the -COOH groups, creating stronger intermolecular attractions than the single hydrogen bonds formed by alkanols (-OH). Greater intermolecular forces require more energy to overcome, giving alkanoic acids higher boiling points.
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Q61. From the graph, it can be inferred that
Athe solubility of X and Y is the same at all temperatures
Bthe solubility of X, Y and Z is temperature dependent
Csolubility of Z increases as temperature increases
Dsolubility of Y increases steadily as temperature increases
Correct Answer: D
From the graph, substance Z has a constant solubility of 40 g/100 cm³ regardless of temperature, eliminating options B and C. Substance X and Y have different solubility values at most temperatures and only intersect once, eliminating option A. Substance Y shows a consistent increase in solubility as temperature rises throughout the entire range, making D the correct inference.
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Q62. Nitrogen, a component of air is used for
Aproduction of cooling agent
Bproduction of margarine
Cproduction of HNO₃
Dmanufacturing of oil
Correct Answer: C
Nitrogen from air is used to produce ammonia (NH₃) via the Haber process, which is then oxidized to nitric acid (HNO₃) via the Ostwald process. Margarine production uses hydrogen, and cooling agents use other gases.
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Q63. CH₃C≡CCH(CH₃)₂. The IUPAC nomenclature of the compound above is
A3-ethyl but-2-yne
B4-methylpent-2-yne
C2-ethyl but-2-yne
D2-methylpent-2-yne
Correct Answer: B
The structure is CH₃-C≡C-CH(CH₃)-CH₃. The longest chain containing the triple bond has 5 carbons (pentyne). Numbering from the end nearer the triple bond: C1=CH₃, C2≡C3, C4=CH with a CH₃ branch, C5=CH₃. The triple bond is at C2 and the methyl branch is at C4. IUPAC name: 4-methylpent-2-yne.
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jamb2025chemistry
Q64. Water drops are spherical in shape because of
Apolarity
Bviscosity
Cdensity
Dsurface tension
Correct Answer: D
Surface tension arises from the cohesive forces between water molecules at the surface. It causes the liquid to minimize its surface area, and the shape with the minimum surface area for a given volume is a sphere. This is why water droplets are spherical.
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Q65. Which of the following gases can be collected by the upward displacement of air?
AChlorine
BAmmonia
CSulphur(IV) oxide
DHydrogen chloride
Correct Answer: B
Ammonia (NH₃, molar mass 17) is lighter than air (molar mass ~29), collected by upward displacement.
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Q66. The oxide that remains unchanged when heated in hydrogen is
ACuO
BPbO
CFe₂O₃
DZnO
Correct Answer: C
Fe₂O₃ resists reduction by hydrogen under standard conditions; CuO, PbO, ZnO reduce to metals.
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jamb2025chemistry
Q67. What is the change in oxidation number of sulfur in the reaction: S + O₂ → SO₂?
A0 to +2
B0 to +4
C+2 to +4
D+4 to +6
Correct Answer: B
Sulfur: 0 in S, +4 in SO₂ (O = -2, 2 × -2 = -4, so S = +4). Change is 0 to +4.
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jamb2025chemistry
Q68. A reaction characteristic of an unsaturated hydrocarbon is
Asubstitution
Baddition
Coxidation
Dhydrolysis
Correct Answer: B
Unsaturated hydrocarbons (e.g., alkenes) undergo addition reactions due to double/triple bonds.
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jamb2025chemistry
Q69. For the reaction 2X + Y → Z, the rate of formation of Z is independent of the concentration of Y and quadruples when the concentration of X is doubled. The rate equation is
AR = k[X][Y]
BR = k[X]²
CR = k[X][Y]²
DR = k[X]²[Y]
Correct Answer: B
Independent of [Y] (order 0), quadruples when [X] doubles (order 2). Rate = k[X]².
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jamb2025chemistry
Q70. For the reaction 2X + Y ⇌ Z, exothermic in the forward direction, a decrease in temperature will
Afavour the reverse reaction
Bfavour the forward reaction
Chave no effect on the equilibrium state
Ddouble the rate of the reverse reaction
Correct Answer: B
Exothermic forward reaction is favored by lower temperature (Le Chatelier’s principle).
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Q71. Pure metals are often used in electrical wiring because
Ametals are ductile
Bmetallic properties are improved in alloys
Calloys are a mixture of metals
Dmetals are strong
Correct Answer: A
Pure metals (e.g., copper) are ductile, drawn into wires, and highly conductive.
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jamb2025chemistry
Q72. The structural formula of 2-methylbutan-2-ol is
ACH₃CH₂CH₂CH₂OH
B(CH₃)₃COH
CCH₃CH(OH)CH₂CH₃
D(CH₃)₂CHCH₂OH
Correct Answer: B
2-methylbutan-2-ol is (CH₃)₃COH, a tertiary alcohol with —OH on the second carbon.
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jamb2025chemistry
Q73. Dehydration of CH₃CH₂CH₂CH₂OH gives
ACH₂=CHCH₂CH₃
BCH₃CH=CHCH₃
CCH₃CH₂CH=CH₂
DCH₂=CHCH=CH₂
Correct Answer: A
Butan-1-ol (CH₃CH₂CH₂CH₂OH) dehydrates to but-1-ene (CH₂=CHCH₂CH₃).
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jamb2025chemistry
Q74. Which of the following is a primary alcohol?
ACH₃CH₂OH
B(CH₃)₂CHOH
C(CH₃)₃COH
DCH₃CH(OH)CH₃
Correct Answer: A
CH₃CH₂OH (ethanol) is primary (—OH on carbon with one other carbon).
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jamb2025chemistry
Q75. The product of the reaction between ethanoic acid and ethanol in the presence of concentrated H₂SO₄ is