Q6655.The nitrogen obtained from air has a density higher than the one from nitrogen-containing compounds because the one from air is contaminated with
Awater vapour
Boxygen
Crare gases
Dcarbon (IV) oxide
Correct Answer: C
Nitrogen obtained from air is contaminated with rare gases (mainly argon), which have higher densities than nitrogen. This makes the density of "atmospheric nitrogen" slightly higher than that of chemically prepared nitrogen.
JAMB (UTME)
Chemistry
2014
Q6656.Water is said to be temporarily hard when it contains
ACa(HCO₃)₂ and Mg(HCO₃)₂ salts
BCa(HCO₃)₂ and CaCO₃ salts
CMg(HCO₃)₂ and CaSO₄ salts
DCaSO₄ and Ca(HCO₃)₂ salts
Correct Answer: A
Temporary hardness is caused by the presence of calcium and magnesium hydrogen trioxocarbonate(IV) salts (Ca(HCO₃)₂ and Mg(HCO₃)₂). It can be removed by boiling.
JAMB (UTME)
Chemistry
2014
Q6657.On exposure to the atmosphere, a hydrated salt loses its water of crystallization to become anhydrous. This phenomenon is referred to as
Aefflorescence
Bdeliquescence
Chygroscopy
Dhydrolysis
Correct Answer: A
Efflorescence is the loss of water of crystallization from a hydrated salt to the atmosphere, resulting in a powder. Deliquescence is the absorption of moisture to form a solution. Hygroscopy is the absorption of moisture without forming a solution.
JAMB (UTME)
Chemistry
2014
Q6658.16.55g of lead (II) trioxonitrate (V) was dissolved in 100g of distilled water at 20°C calculate the solubility of the solute in moldm⁻³ [Pb = 207, N = 14, O = 16]
Q6659.The dispersion of a liquid in a liquid medium will give
Aan emulsion
Ba fog
Ca gel
Dan aerosol
Correct Answer: A
An emulsion is a dispersion of one liquid in another immiscible liquid. A fog is a liquid dispersed in a gas. A gel is a solid dispersed in a liquid. An aerosol is a liquid or solid dispersed in a gas.
JAMB (UTME)
Chemistry
2014
Q6660.The major and most effective way of controlling pollution is to
Aimprove machinery so that the substances released from combustion are less harmful
Bpass strict laws against it by individuals and companies
Ceducate people on the causes and effects of pollution
Dconvert chemical wastes to harmless substances before releasing them into the environment
Correct Answer: D
The most effective way to control pollution is to convert chemical wastes into harmless substances before releasing them into the environment (waste treatment). This addresses the problem at the source.
JAMB (UTME)
Chemistry
2014
Q6661.The basicity of CH₃COOH is
A4
B1
C2
D3
Correct Answer: B
Basicity is the number of replaceable hydrogen ions (H⁺) produced by one molecule of the acid. CH₃COOH (ethanoic acid) is a monobasic acid (basicity = 1) because it has one replaceable hydrogen.
JAMB (UTME)
Chemistry
2014
Q6662.The colour of litmus in a neutral medium is
Apurple
Bpink
Cyellow
Dorange
Correct Answer: A
Litmus is purple in neutral medium, red in acidic medium, and blue in alkaline medium.
JAMB (UTME)
Chemistry
2014
Q6663.The mathematical expression of pH is
Alog₁₀[OH⁻]
Blog₁₀(1/[H₃O⁺])
Clog₁₀[H₃O⁺]
Dlog₁₀(1/[OH⁻])
Correct Answer: B
pH = -log₁₀[H₃O⁺] = log₁₀(1/[H₃O⁺]).
JAMB (UTME)
Chemistry
2014
Q6664.Which of the following salts will turn blue litmus red?
ASodium tetrahydroxozinate (II)
BPotassium hydrogen tetraoxosulphate (IV)
CSodium trioxocarbonate (IV)
DZinc chloride hydroxide
Correct Answer: B
Potassium hydrogen tetraoxosulphate(IV) (KHSO₄) is an acid salt that produces H⁺ ions in solution, turning blue litmus red. Sodium tetrahydroxozinate(II) and sodium trioxocarbonate(IV) are basic. Zinc chloride hydroxide is amphoteric.
JAMB (UTME)
Chemistry
2014
Q6665.Zn(s) + CuSO₄(aq) → ZnSO₄(aq) + Cu(s)
A0 to +4
B0 to +2
C+1 to +2
D+1 to +3
Correct Answer: B
The reducing agent is Zn, which is oxidized from 0 to +2. Zn loses electrons to form Zn²⁺.
JAMB (UTME)
Chemistry
2014
Q6666.H₂O(g) + C(s) → H₂(g) + CO(g)
AH₂O
BC
CH₂
DCO
Correct Answer: A
H₂O is reduced (H goes from +1 to 0 in H₂), so it is the oxidizing agent. C is oxidized (from 0 to +2 in CO), so it is the reducing agent.
JAMB (UTME)
Chemistry
2014
Q6667.Calculate the quantity of electricity in coulombs required to liberate 10g of copper from a copper compound [Cu = 64, F = 96500 C mol⁻¹]
A32395.5
B30156.3
C60784.5
D15196.5
Correct Answer: B
Cu²⁺ + 2e⁻ → Cu. Moles of Cu = 10/64 = 0.15625 mol. Moles of electrons = 2 × 0.15625 = 0.3125 mol. Quantity of electricity = 0.3125 × 96500 = 30156.25 C ≈ 30156.3 C.
JAMB (UTME)
Chemistry
2014
Q6668.How many faraday of electricity is required to produce 0.25 mole of copper?
A1.00F
B0.01F
C0.05F
D0.50F
Correct Answer: D
Cu²⁺ + 2e⁻ → Cu. 1 mole of Cu requires 2 moles of electrons = 2F. For 0.25 mole of Cu, required = 0.25 × 2 = 0.50F.
JAMB (UTME)
Chemistry
2014
Q6669.Z in diagram below represents...
Aheat of reaction
Bactivation energy
Cfree energy
Dentropy of reaction
Correct Answer: A
In the energy profile diagram, Z represents the heat of reaction (enthalpy change, ΔH), which is the difference in energy between reactants and products.
JAMB (UTME)
Chemistry
2014
Q6670.If the change in free energy of a system is -899 Jmol⁻¹ and the entropy change is 10 Jmol⁻¹K⁻¹ at 25°C calculate the enthalpy change.
Increasing the concentration of H⁺ (a product) will shift the equilibrium to the left (reverse reaction) according to Le Chatelier's principle.
JAMB (UTME)
Chemistry
2014
Q6674.Which of the following will liberate hydrogen from dilute tetraoxosulphate (VI) acid?
ALead
BMagnesium
CCopper
DGold
Correct Answer: B
Magnesium is more electropositive than hydrogen and will liberate hydrogen from dilute H₂SO₄. Lead forms an insoluble sulphate coating. Copper and gold are less reactive than hydrogen.
JAMB (UTME)
Chemistry
2014
Q6675.In the diagram, the function of the concentrated H₂SO₄ is to
Apurify the gas
Bdry the gas
Cliquefy the gas
Dremove odour
Correct Answer: B
Concentrated H₂SO₄ is used as a drying agent to remove water vapour from the gas.
JAMB (UTME)
Chemistry
2014
Q6676.The gas that is removed by the water in the flask is
AO₂
BSO₂
CHCl
DCl₂
Correct Answer: C
The water in the flask removes HCl gas (which is highly soluble in water). The concentrated H₂SO₄ then dries the remaining gas (chlorine).
JAMB (UTME)
Chemistry
2014
Q6677.Fluorine does not occur in the free state in nature because
Ait is a poisonous gas
Bit belongs to the halogen family
Cit is inert
Dof its high reactivity
Correct Answer: D
Fluorine is extremely reactive and cannot exist in the free state in nature. It is always found combined with other elements.
JAMB (UTME)
Chemistry
2014
Q6678.In the extraction of sodium from fused sodium chloride, the anode is made of platinum because
Asodium is formed at the anode
Bchlorine is formed at the anode
Csodium does not react with platinum
Dchlorine does not react with platinum
Correct Answer: D
Chlorine gas is produced at the anode during the electrolysis of fused NaCl. Platinum is used because it is inert and does not react with chlorine.
JAMB (UTME)
Chemistry
2014
Q6679.A compound that gives a brick-red colour to a non-luminous flame is likely to contain
Acopper ions
Bsodium ions
Ccalcium ions
Daluminium ions
Correct Answer: C
Calcium ions (Ca²⁺) give a brick-red colour to a non-luminous flame in flame tests.
JAMB (UTME)
Chemistry
2014
Q6680.In the electrolytic extraction of calcium from calcium chloride, the cathode is
Azinc
Bgraphite
Cplatinum
Diron
Correct Answer: D
In the electrolytic extraction of calcium, the cathode is made of iron. Calcium is deposited at the cathode.
JAMB (UTME)
Chemistry
2014
Q6681.A few drops of NaOH solution was added to an unknown salt forming a white precipitate which is insoluble in excess solution. The cation likely present is
AZn²⁺
BPb²⁺
CCa²⁺
DAl³⁺
Correct Answer: C
Ca²⁺ forms a white precipitate of Ca(OH)₂ with NaOH, which is insoluble in excess NaOH. Zn²⁺, Pb²⁺, and Al³⁺ form precipitates that dissolve in excess NaOH.
JAMB (UTME)
Chemistry
2014
Q6682.The general formula of haloalkanes where X represents the halide is
ACₙH₂ₙ₋₁X
BCₙH₂ₙX
CCₙH₂ₙ₊₁X
DCₙH₂ₙ₊₂X
Correct Answer: C
Haloalkanes are derivatives of alkanes (CₙH₂ₙ₊₂) where one hydrogen is replaced by a halogen. The general formula is CₙH₂ₙ₊₁X.
JAMB (UTME)
Chemistry
2014
Q6683.The IUPAC nomenclature of the compound above is
A2-bromo-3-chlorobutanol
B3-bromo-2-chlorobutanol
C3-chloro-2-bromobutanol
D2-chloro-3-bromobutanol
Correct Answer: D
The longest chain has 4 carbons (butane). The -OH group is on carbon 1 (butanol). Numbering from the end closer to the substituents: Cl on C2, Br on C3. The correct name is 2-chloro-3-bromobutan-1-ol.
JAMB (UTME)
Chemistry
2014
Q6684.The alkanol obtained from the production of soap is
Apropanol
Bethanol
Cglycerol
Dmethanol
Correct Answer: C
Saponification of fats and oils produces soap and glycerol (propane-1,2,3-triol).
JAMB (UTME)
Chemistry
2014
Q6685.Ethyne is passed through a hot tube containing organo-nickel catalyst to produce
Aisoprene
Bpolythene
Cethanol
Dbenzene
Correct Answer: D
Ethyne (acetylene) undergoes cyclization when passed through a hot tube containing an organo-nickel catalyst to produce benzene.
JAMB (UTME)
Chemistry
2014
Q6686.Due to the unstable nature of ethyne, it is stored by dissolving in
Aethane-1,2-diol
Bpropanol
Cethanoic acid
Dpropanone
Correct Answer: D
Ethyne is stored by dissolving it in propanone (acetone) under pressure. This is because ethyne is unstable and can explode if compressed alone.
JAMB (UTME)
Chemistry
2014
Q6687.The process of converting starch to ethanol is
Acracking
Bdistillation
Cfermentation
Doxidation
Correct Answer: C
Fermentation is the process by which starch is converted to ethanol using yeast (zymase enzyme).
JAMB (UTME)
Chemistry
2014
Q6688.The polymer used in making car rear lights is
APerspex
BBakelite
Cpolystyrene
Dpolyacrylonitrile
Correct Answer: D
Polyacrylonitrile (PAN) is used in making car rear lights because it is transparent, strong, and heat-resistant.
H⁺ acts as a catalyst to increase the rate of hydrolysis of the ester. It does not affect the equilibrium position (yield).
JAMB (UTME)
Chemistry
2014
Q6690.A hydrocarbon has an empirical formula CH and a vapour density of 39. Determine its molecular formula. [C = 12, H = 1]
AC₂H₆
BC₃H₈
CC₃H₄
DC₆H₆
Correct Answer: D
Empirical formula mass = 12 + 1 = 13. Molecular mass = 2 × vapour density = 2 × 39 = 78. n = 78/13 = 6. Molecular formula = (CH)₆ = C₆H₆.
JAMB (UTME)
Chemistry
2014
Q6691.Polystyrene is widely used as packaging materials for fragile objects during transportation because of its
Alightness
Blow density
Chigh density
Dhigh compressibility
Correct Answer: B
Polystyrene foam has very low density and is an excellent shock absorber, making it ideal for packaging fragile objects.
JAMB (UTME)
Chemistry
2014
Q6692.The process of converting linear alkanes to branched chain and cyclic hydrocarbons by heating in the presence of a catalyst to improve the quality of petrol is referred to as
Arefining
Bcracking
Creforming
Dblending
Correct Answer: C
Reforming is the process of converting straight-chain alkanes into branched-chain and cyclic hydrocarbons (aromatics) to improve the octane rating of petrol.
JAMB (UTME)
Chemistry
2014
Q6693.The petroleum fraction that is used in heating furnaces in industries is
Adiesel oil
Bgasoline
Ckerosene
Dlubricating oil
Correct Answer: A
Diesel oil is used in industrial heating furnaces and diesel engines. Gasoline is for cars, kerosene for lamps and jet fuel, and lubricating oil for lubrication.
Instruction
JAMB Chemistry 2015
JAMB (UTME)
Chemistry
2015
Q6694.Which of the following statements is correct?
AThe average kinetic energy of a gas is directly proportional to its temperature
BAt constant temperature, the volume of a gas increases as the pressure increases.
CThe pressure of a gas is inversely proportional to its volume.
DThe temperature of gas is directly proportional to its volume.
Correct Answer: A
The average kinetic energy of gas molecules is directly proportional to the absolute temperature (Kelvin). This is a fundamental postulate of the kinetic theory of gases. Option B is incorrect (volume decreases as pressure increases at constant temperature). Option C is correct only at constant temperature (Boyle's Law), but the statement is incomplete. Option D is correct only at constant pressure (Charles's Law), but the statement is incomplete.
JAMB (UTME)
Chemistry
2015
Q6695.Which are the correct IUPAC names for H-CO₂CH₃ and CH≡CH
AMethyl methanoate and ethene
BMethanoic acid and ethyne
CEthyl methanoate and ethyne
DMethyl methanoate and ethyne
Correct Answer: D
H-CO₂CH₃ is an ester formed from methanoic acid and methanol. Its IUPAC name is methyl methanoate. CH≡CH is ethyne (acetylene).
JAMB (UTME)
Chemistry
2015
Q6696.A solution X on mixing with AgNO₃ solution, gives a white precipitate soluble in NH₃(aq). A solution Y, when added to X, also gives a white precipitate which is soluble on boiling. Solution Y contains
AAg⁺ ion
BPb²⁺ ion
CPb⁴⁺ ion
DZn²⁺ ion
Correct Answer: B
X gives a white precipitate with AgNO₃ that is soluble in ammonia — this indicates Cl⁻ ions in X (AgCl is white and soluble in NH₃). Y gives a white precipitate with X (Cl⁻) that is soluble on boiling — this indicates Pb²⁺ ions (PbCl₂ is white and soluble in hot water).
JAMB (UTME)
Chemistry
2015
Q6697.Methane is a member of the homologous series called
Aalkenes
Balcohols
Cesters
Dalkanes
Correct Answer: D
Methane (CH₄) is the first member of the alkane homologous series with the general formula CₙH₂ₙ₊₂.
JAMB (UTME)
Chemistry
2015
Q6698.Which of the following bonds exists in crystalline ammonium chloride (NH₄Cl)?
Aionic covalent
Bionic and co-ordinate
Cionic, covalent and co-ordinate
Dcovalent, co-ordinate and metallic
Correct Answer: C
NH₄Cl contains ionic bonds (between NH₄⁺ and Cl⁻), covalent bonds (within NH₄⁺ between N and H), and coordinate (dative) bonds (in the formation of NH₄⁺ where N donates a lone pair to H⁺).
JAMB (UTME)
Chemistry
2015
Q6699.Some copper (II) sulphate pentahydrate (CuSO₄·5H₂O), was heated at 120°C with the following results: Wt of crucible = 10.00 g; Wt of crucible + CuSO₄·5H₂O = 14.98g; Wt of crucible + residue = 13.54g. How many molecules of water of crystallization were lost? [H = 1, Cu = 63.5, O = 16, S = 32]
A1
B2
C3
D4
Correct Answer: C
Mass of CuSO₄·5H₂O = 14.98 - 10.00 = 4.98 g. Mass of residue (CuSO₄) = 13.54 - 10.00 = 3.54 g. Mass of water lost = 4.98 - 3.54 = 1.44 g. Moles of CuSO₄ = 3.54/159.5 = 0.0222 mol. Moles of H₂O = 1.44/18 = 0.08 mol. Ratio = 0.08/0.0222 ≈ 3.6 ≈ 3 (approximately). (The question and options may have errors).
JAMB (UTME)
Chemistry
2015
Q6700.Which of the curves shown above represents the relationships between the volume (v) and pressure (p) of an ideal gas at constant temperature?
A1
B2
C3
D4
Correct Answer: C
At constant temperature, volume is inversely proportional to pressure (Boyle's Law). The graph of V against P is a hyperbola. The curve that represents this is curve 3 (likely the one showing inverse relationship).