Chemistry JAMB, WAEC, NECO AND NABTEB Official Past Questions

757

Which of the following could not be alkane?

  • A. C\(_4\)H\(_{10}\)
  • B. C\(_5\)H\(_{12}\)
  • C. C\(_7\)H\(_{14}\)
  • D. C\(_8\)H\(_{18}\)
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758

The two ions responsible for hardness in water are

  • A. Ca\(^{2+}\) and / or Mg\(^{2+}\)
  • B. K\(^+\) and / or Mg\(^{2+}\)
  • C. Ca\(^{2+}\) and / or Li\(^+\)
  • D. Ca\(^{2+}\) and / or Na\(^+\)
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759

What volume of 0.100M sodium trioxonitrate (V) solution contains 5g of solute.
[Na = 23, N = 14, O = 16]

  • A. 1.7 litres
  • B. 0.420 litres
  • C. 0.588 litres
  • D. 2.35 litres
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760

Elements in the periodic table are arranged in the order of their

  • A. atomic numbers
  • B. metallic character
  • C. mass number
  • D. relative atomic mass
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761

Which important nitrogen-containing compound is produced in Haber’s process?

  • A. NH\(_3\)
  • B. NO\(_2\)
  • C. NO
  • D. HNO\(_3\)
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762

What mass of magnesium would be obtained by passing a current of 2 amperes for 2 hours 30 mins, through molten magnesium chloride?
[1 faraday = 96500C, Mg = 24]

  • A. 1.12g
  • B. 4.48g
  • C. 1.80g
  • D. 2.00g
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763

Which of the following gases contains the least number of atoms at s.t.p?

  • A. 1 mole of butane
  • B. 4 moles of chlorine
  • C. 3 moles of ozone
  • D. 7 moles of argon
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764

The IUPAC nomenclature of the compound
H\(_3\)C – CH(CH\(_3\)) – CH(CH\(_3\)) – CH\(_2\) – CH\(_3\)

  • A. 3,4- dimethylhexane
  • B. 2,3- dimethyl pentane
  • C. 2- ethyl hexane
  • D. 2,3- dimethylhexane
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765

A compound contains 40.0% carbon, 6.7% hydrogen and 53.3% oxygen. If the molar mass of the compound is 180. Find the molecular formula.
[H = 1, C = 12, O = 16]

  • A. C\(_3\)H\(_6\)O\(_3\)
  • B. C\(_6\)H\(_6\)O\(_3\)
  • C. C\(_6\)H\(_{12}\)O\(_6\)
  • D. CH\(_2\)O
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766

In the reaction:
M + N → P
ΔH = +Q kJ

Which of the following would increase the concentration of the product?

  • A. Adding a suitable catalyst
  • B. Increasing the concentration of P
  • C. Increasing the temperature
  • D. Decreasing the temperature
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767

Sulphur exists in six forms in the solid state. This property is known as

  • A. Isomerism
  • B. Allotropy
  • C. Isotopy
  • D. Isomorphism
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768

In the reaction between sodium hydroxide and tetraoxosulphate (VI) solutions, what volume of 0.5 molar sodium hydroxide would exactly neutralize 10cm\(^3\) of 1.25 molar tetraoxosulphate (vi) acid?

  • A. 25cm\(^3\)
  • B. 10cm\(^3\)
  • C. 20cm\(^3\)
  • D. 50cm\(^3\)
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769

Which of the following is a physical change?

  • A. Exposing white phosphorus to air
  • B. Burning kerosene
  • C. Dissolving calcium in water
  • D. Freezing ice cream
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770

Consider the equation below:

Cr\(_2\)O\(_7 ^{2-}\) + 6Fe\(^{2+}\) + 14H\(^{+}\) \(\to\) 2Cr\(^{3+}\) + 6Fe\(^{3+}\) + 7H\(_2\)O.

The oxidation number of chromium changes from

  • A. +5 to +3
  • B. +6 to +3
  • C. -2 to +3
  • D. +7 to +3
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771

Which of the following pairs cannot be represented with a chemical formula?

  • A. air and bronze
  • B. bronze and sodium chloride
  • C. copper and sodium chloride
  • D. caustic soda and washing soda
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772

Which of the following describes the chemical property of acids?

  • A. None of the above
  • B. Acid + XCO\(_3\) \(\to\) Salt + H\(_2\)O + NH\(_3\)
  • C. Acid + NaOH \(\to\) Normal salt + CO\(_2\)
  • D. Acid + X\(_n\)CO\(_3\) \(\to\) Salt + H\(_2\)O + CO\(_2\)
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773

Which of the following pollutants will lead to the depletion of ozone layer?

  • A. chlorofluorocarbon
  • B. carbon (ii) oxide
  • C. hydrogen sulphide
  • D. sulphur (iv) oxide
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774

Which two gases can be used for the demonstration of the fountain experiment?

  • A. SO\(_4\) and NH\(_3\)
  • B. SO\(_3\) and NH\(_3\)
  • C. HCl and NH\(_3\)
  • D. SO\(_2\) and CO
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775

A radioactive nucleus has a half-life of 20 years, starting with 100,000 particles, how many particles will be left exactly at the end of 40 years

  • A. 75,000 particles
  • B. 35,000 particles
  • C. 25,000 particles
  • D. 50,000 particles
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776

Na\(_2\)CO\(_3\) + 2HCl \(\to\) 2NaCl + H\(_2\)O + CO\(_2\)

The indicator most suitable for this reaction should have a pH equal to

  • A. 5
  • B. 7
  • C. 3
  • D. 9
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777

The molecular shape and bond angle of water are respectively

  • A. linear, 180°
  • B. bent, 109.5°
  • C. tetrahedral, 109.5°
  • D. bent, 105°
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