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Chemistry Past Questions

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4,306 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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4,306 questions

Question 1 of 20 4,306 total questions

Question 1921

jamb 1987

An element Z, contained 90% of ¹⁶₈Z and 10% of Z¹⁸₁₈ its relative atomic mass is?

A16.0

B16.2

C17.0

D17.8

View Explanation & Discuss

Question 1922

jamb 1987

An isotope has an atomic number of 17 and a mass number of 36. Which of the following gives the correct number of neutrons and protons in an atom of the isotope?

ANeutrons 53, Protons 17

BNeutrons 17, Protons 36

CNeutrons 19, Protons 17

DNeutrons 36, Protons 17

View Explanation & Discuss

Question 1923

jamb 1987

If d represents the density of a gas and K is a constant, the rate of gaseous diffusion r is related to d by the equation?

Ar = k/√d

Br = kd

Cr =k/d

Dr = k √d

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Question 1924

jamb 1987

The atomic numbers of two elements X and Y are 12 and 19 respectively. The bond of these two elements is?

Aionic

Bcovalent

CMetallic

Dco-ordinate

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Question 1925

jamb 1987

If 24.83 cm³ of 0.15 M NaOH is titrated to its end point with 39.45 cm³
of HCl, what is the molarity of the HCl?

A0.094 M

B0.150 M

C0.940 M

D1.500 M

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Question 1926

jamb 1987

In which of the following are the aqueous solutions of each of the substances correctly arranged in order to decreasing acidity?

AEthanoic acid, milk or magnesia, sodium chloride, hydrochloric acid and sodium hydroxide

BEthanoic acid, hydrochloric acid, milk of magnesia, sodium chloride and sodium chloride and sodium hydroxide

CHydrochloride acid, ethanol acid, sodium chloride, milk of magnesia and sodium hydroxide

DHydrochloride acid, sodium hydroxide sodium chloride, ethanol acid, and milk of magnesia

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Question 1927

jamb 1987

The solubility of Na3AsO4(H2O)12 is 38.9g per 100g H2O. What is the mass percentage of Na3AsO4 in the saturated solution?

(As = 75, Na = 23, O = 16, H = 1)

A87.27%

B38.9%

C19.1%

D13.7%

View Explanation & Discuss

Question 1928

jamb 1987

Oil spillage in ponds and creeks can be cleaned up by?

Aburning off the oil layer

Bspraying with detergent

Cdispersal with compressed air

Dspraying with hot water

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Question 1929

jamb 1987

Which of the following water samples will have the highest titre value when titrated for the Ca²⁺ ions using soap solution?

APermanently hard water after boiling

Bemporarily hard water after boiling

CRain water stored in a glass jar for two years

DPermanent hard water passed through permuitit

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Question 1930

jamb 1987

In the purification of town water supply, alum is used principally to?

Akill bacteria

Bcontrol the pH of water

Cimprove the taste of the water

Dcoagulate small pasrticles of mud

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Question 1931

jamb 1987

A stream of air was successively passed through three tubes X, Y and Z containing a concentrated aqueous solution of KOH, red hot copper powder and fused calcium chloride respectively. What was the composition of the gas emanating from tube Z?

ACO₂ ad ithe inert gases

BN₂, CO₂ and the inert gases

CN₂ and the inert gases

Dwater vapour, N₂ and the inert gases

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Question 1932

jamb 1987

The greater the different in electronegativity between bonded atoms, the?

Alower the polarity of the bond

Bhigher the polarity of the bond

Cweaker the bond

Dhigher the possibility of the substance formed being a molecule

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Question 1933

jamb 1987

When water drops are added to calcium carbide in a container and the gas is passed through a jet and lifted, the resultant flame is called an?

Aoxyethylene flame

Boxyhydrocarbon flame

Coxyacetylene flame

Doxymethane flame

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Question 1934

jamb 1987

Complete oxidation of propan -1- ol gives?

Apropanal

Bpropan-2-al

Cpropan-1-one

Dpropanoic acid

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Question 1935

jamb 1987

Synthetic rubber is made by polymerization of

A2 methyl buta - 1, 3 - diene

B2 methyl buta - 1, 2 - diene

C2 methyl but -1-ene

D2 methyl but-2-ene

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Question 1936

jamb 1987

Local black soap is made by boiling palm oil with liquid extract of ash. The function of the ash is to provide the?

Aacid

Bester of allanoic acid

Calkali

Dalkanol

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Question 1937

jamb 1987

The most volatile fraction obtained from fractional distillation of crude petroleum contains?

Abutane , propane and kerosene

Bbutane , propane and petrol

Cethane, methane and benzene

Dmethane, ethane and propane

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Question 1938

jamb 1987

Ethanol reacts with aqueous sodium mono-oxoio date (l) to give a bright yellow solid with a characteristic smell. The product is?

Atrichloromethane

Btriodomethane

Ciodoethane

Dethanal

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Question 1939

jamb 1987

The efficiency of petrol as a fuel in high-compression internal combustion engines improves with an increase in the amount of?

Abranched chain alkanes

Bstraight chain alkanes

Ccycloalkanes

Dhalogenated hydrocarbons

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Question 1940

jamb 1987

Which of the following compounds will give a precipitate with an aqueous ammoniacal solution of copper (l) chloride?

ACH₃ = CHCH₃

BCH₃ ≡ CCH₃

CHC = C-CH₂CH₃

DCH₂ = CH-CH = CH₂

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