Chemistry JAMB, WAEC, NECO AND NABTEB Official Past Questions

1891

Which of the following organic compounds would decolourize bromie water?

  • A. Benzene
  • B. Cyclobutane
  • C. Hexane
  • D. Pentane
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1892

The major product formed by the reaction between ethanoic acid and aqueous sodium hydroxide is

  • A. soap
  • B. sodium ethanoate
  • C. sodium methoxide
  • D. water
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1893

The separation of petroleum fractions depends on the differences in their

  • A. melting points
  • B. molar masses
  • C. solubilities
  • D. boiling points
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1894

Consider the redox reaction as represented by the following equation: 12(aq) + 2S2O32-(aq) → 21(aq) + S4O62-(aq). Which of the species in the equation is reduced?

  • A. S4O62-(aq)
  • B. S4O32-(aq)
  • C. 12(aq)
  • D. 1-(aq)
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1895

Which of the following cells produce electrical energy from chemical reactions?
l. Lead-acid battery ll. Dry cell III. Deniell cell IV Electrolytic cell

  • A. l and ll only
  • B. l, ll, and III only
  • C. lll and IV only
  • D. I and III only
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1896

Consider the reaction represented by the equation: N2O4(g) ⇌ 2NO2(g) ; ∆H = + x kJmol-1
What happens when the temperature is reduced at equilibrium?

  • A. Concentration of N 2O4(g) decreases
  • B. Concentration of N 2O4(g) increases.
  • C. Pressure exerted by the gases increases
  • D. Pressure exerted by the gases remains constant
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1897

The following factors affect the solubility of a solid in a given solvent except

  • A. nature of solute
  • B. nature of solvent
  • C. pressure
  • D. temperature
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1898

A substance is said to be impure if

  • A. its melting point range is wide
  • B. it dissolves in water with difficult
  • C. it has a low melting point
  • D. it is coloured
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1899

Which of the following compounds crystallizes without water of crystallization?

  • A. MgSO4
  • B. Na2CO3
  • C. NaCI
  • D. FeSO4
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1900

Which of the following acids would readily react with CaCO3 to liberate CO2?

  • A. CH3COOH
  • B. H2SO4
  • C. H2SO3
  • D. HNO3
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1901

The aqueous solution which has pH > 7 is

  • A. FeCI3(aq)
  • B. CuSO4(aq)
  • C. KNO3(aq)
  • D. Na2CO3(aq)
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1902

When heat is absorbed during a chemical reaction, the reaction is said to be

  • A. adiabatic
  • B. endothermic
  • C. exothermic
  • D. isothermal
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1903

Which of the following variables is a measure of the average kinetic energy of the molecule of a gas?

  • A. Density
  • B. Pressure
  • C. Temperature
  • D. Volume
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1904

Which of the following gases are arranged in increasing order of diffusion rate? [H = 1 .0; C = 12; N = 14; O = 16; S = 32]

  • A. SO 2 O2, NH3 H2
  • B. H2S,NH2,O2,SO2
  • C. CO2,N2O,O2,SO2
  • D. NH3,NO2,N2,CO2
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1905

The pressure exerted by a gas is a function of the

  • A. total volume of the gas
  • B. speed of the gaseous molecules
  • C. mass of each gaseous molecule
  • D. frequency of collision between gaseous molecules
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1906

Which of the following phenomenna lead to decrease in volume of a liquid in an open container?

  • A. Brownian motion
  • B. Diffusion
  • C. Evaporation
  • D. Sublimation
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1907

The gas law which describes the relationship between volume and temperature is

  • A. Boyle's law
  • B. Charles' law
  • C. Dalton's law
  • D. Graham's law
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1908

The percentage by mass of calcium in Ca(OCI)2 is [Ca = 40.0; CI = 35.5; O = 16.0]

  • A. 28.0%
  • B. 31.6%
  • C. 43.8%
  • D. 44.5%
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1909

The volume of 0.25 moldm-3 solution of KOH that would yield 6.5g of of solid KOH on evaporation is (K = 39.0; o = 16.0; H = 1.00)

  • A. 464.30 cm3
  • B. 625.00 cm3
  • C. 1000.00 cm3
  • D. 2153.80 cm3
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1910

Consider the reaction represented by the following equation: C\(_2\)H\(_2\) + yH\(_2\) → C\(_2\)H\(_6\). The value of y in the reaction is

  • A. 4
  • B. 3
  • C. 2
  • D. 1
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1911

Which of the following statements about nuclear reaction is correct? The reaction

  • A. involves neutrons only
  • B. takes place inside the nucleus
  • C. is governed by temperature and pressure
  • D. involves protons and electrons only
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