General Chemistry I — 2025B Past Questions

University of Ilorin CHM101: 128 questions.

Topics: Hybridisation and shapes of simple molecules, Acids, Bases and Salts, Modern electronic theory of atoms, Atoms, elements, molecules, Properties of gases, Electronic configuration, Periodicity and building up of the periodic table, Redox reactions and introduction to electrochemistry

  1. Which of the following salts is not acidic?
    1. CH₃COONa
    2. NH₄Cl
    3. CuCl₃
    4. CuSO₄
  2. On the periodic table, Boron has lower ionization energy than Beryllium. Why?
    1. 2p orbital has higher energy than 2s orbital
    2. It has a smaller atomic radius
    3. Beryllium is more stable than Boron
    4. None of these
  3. Which of these is amphiprotic?
    1. HCl
    2. NH₃
    3. HF
    4. HCO₃⁻
  4. Which is the weakest acid?
    1. HNO₃
    2. H₃PO₄
    3. H₂PO₄⁻
    4. HPO₄²⁻
  5. HOBr + OH⁻ → H₂O + Br⁻. Identify the Brønsted base.
    1. HOBr
    2. OH⁻
    3. H₂O
    4. Br⁻
  6. The shape of hydrogen sulfide is
    1. Trigonal pyramidal
    2. Tetrahedral
    3. Bent
    4. None of the above
  7. The steric number of a molecule having 2 lone pairs and 3 bond pairs is
    1. 3
    2. 2
    3. 5
    4. 1
  8. Which of the following is isoelectronic with Neon?
    1. O²⁻
    2. Mg
    3. Ca
    4. K⁺
  9. Arrange these in order of increasing energy: 4s, 4p, 3d.
    1. 4s < 4p < 3d
    2. 4s < 3d < 4p
    3. 3d < 4s < 4p
    4. 3d < 4p < 4s
  10. Which of the following pairs are isotones?
    1. ¹H and ²H
    2. ²²Ne and ²³Na
    3. ¹⁴C and ¹⁸O
    4. ³²S and ³⁵Cl
  11. When NaHCO₃ is dissolved in water, the resulting solution is
    1. Acidic
    2. Neutral
    3. Basic
    4. None
  12. HF + H₂O → H₃O⁺ + F⁻. What is true about this equation?
    1. HF is the conjugate acid while F⁻ is the base
    2. HF is the base while F⁻ is the conjugate acid
    3. HF is the acid while F⁻ is the conjugate base
    4. HF is the conjugate base while F⁻ is the acid
  13. How many lone pairs are there in CH₄ and its steric number respectively?
    1. 4, 0
    2. 2, 2
    3. 1, 3
    4. 0, 4
  14. Al³⁺ and Na⁺ are what kind of pair of elements?
    1. Isoelectronic
    2. Isotopes
    3. Isobars
    4. Isotones
  15. What does the principal quantum number represent?
    1. Angular momentum of an electron
    2. Energy of shells
    3. Orientation of the subshells
    4. Shape of an orbital
  16. For which of the following is the difference between the neutron number and mass number positive?
    1. Hydrogen
    2. Tritium
    3. Protium
    4. None of the above
  17. Which quantum number determines the angular momentum of an electron?
    1. Principal
    2. Spin
    3. Azimuthal
    4. Magnetic
  18. Between 16 g/mol gas and 64 g/mol gas, which one effuses faster?
    1. 64 g/mol
    2. 16 g/mol
    3. They will effuse at the same time
    4. Cannot be determined
  19. Which has the highest acidity in these: HF, H₂S, H₂Se, H₂Te?
    1. HF
    2. H₂S
    3. H₂Se
    4. H₂Te
  20. What do these have in common: ¹⁴C₆, ¹⁵N₇, ¹⁶O₈?
    1. Isotopy
    2. Isobaric
    3. Isotones
    4. Isoelectronic
  21. In the compound CuSO₄²⁻, what contributes to the acidity?
    1. SO₄²⁻
    2. Cu
    3. Both
    4. None
  22. Which gas law is applied when a balloon pops after being sat on?
    1. Law of pressure gradient
    2. Boyle’s Law
    3. Charles’ Law
    4. None of the above
  23. Which rule does this obey: 1s², 2s², 2pₓ, 2pᵧ?
    1. Pauli’s Exclusion Principle
    2. Hund’s Principle
    3. Aufbau’s Principle
    4. None
  24. What is the angle of see-saw geometry?
    1. 90°
    2. 120°
    3. 180°
    4. 109.5°
  25. From Graham’s Law, the rate of a chemical reaction is inversely proportional to:
    1. Density
    2. Square root of molar mass
    3. Mass
    4. Volume
  26. When a neutral atom gains an electron to become an anion, its energy
    1. Increases
    2. Decreases
    3. Remains the same
    4. None of the above
  27. Which of the following does not affect the acidity of oxoacids?
    1. The electronegativity of the central atom
    2. The size of the hydrogen atom
    3. The valence electron of the acid
    4. None of the above
  28. PF₃ has how many lone pairs of electrons?
    1. 1
    2. 2
    3. 3
    4. 4
  29. SF₄ has how many lone pairs of electrons?
    1. 1
    2. 2
    3. 0
    4. 3
  30. A compound with sweet taste has which molecular geometry?
    1. Trigonal pyramidal
    2. Octahedral
    3. Tetrahedral
    4. Linear
  31. NH₃ has how many steric number?
    1. 1
    2. 2
    3. 3
    4. 4
  32. If azimuthal number is 2, what is the magnetic number?
    1. 0
    2. 3
    3. 5
    4. 7
  33. Which of the following is isotonic to ⁷⁶X₃₂?
    1. ⁷⁷Y₃₂
    2. ⁷⁸Z₃₄
    3. ⁷⁷A₃₅
    4. ⁷⁸W₃₃
  34. Which acid has the highest strength?
    1. HClO₃
    2. HClO₂
    3. HClO
    4. HOCl
  35. The electrons in the ground state of an element are arranged in which order in the shells?
    1. Increasing
    2. Decreasing
    3. Anyhow
    4. None of the above
  36. How many lone pairs are there in CH₄ and its steric number respectively?
    1. 4, 0
    2. 2, 2
    3. 1, 3
    4. 0, 4
  37. Al³⁺ and Na⁺ are what kind of pair of elements?
    1. Isoelectronic
    2. Isotopes
    3. Isobars
    4. Isotones
  38. What does the principal quantum number represent?
    1. Angular momentum of an electron
    2. Energy of shells
    3. Orientation of the subshells
    4. Shape of an orbital
  39. For which of the following is the difference between the neutron number and mass number positive?
    1. Hydrogen
    2. Tritium
    3. Protium
    4. None of the above
  40. Which quantum number determines the angular momentum of an electron?
    1. Principal
    2. Spin
    3. Azimuthal
    4. Magnetic
  41. Between 16 g/mol gas and 64 g/mol gas, which one effuses faster?
    1. 64 g/mol
    2. 16 g/mol
    3. They will effuse at the same time
    4. Cannot be determined
  42. Which has the highest acidity in these: HF, H₂S, H₂Se, H₂Te?
    1. HF
    2. H₂S
    3. H₂Se
    4. H₂Te
  43. What do these have in common: ¹⁴C₆, ¹⁵N₇, ¹⁶O₈?
    1. Isotopy
    2. Isobaric
    3. Isotones
    4. Isoelectronic
  44. In the compound CuSO₄²⁻, what contributes to the acidity?
    1. SO₄²⁻
    2. Cu
    3. Both
    4. None
  45. Which gas law is applied when a balloon pops after being sat on?
    1. Law of pressure gradient
    2. Boyle’s Law
    3. Charles’ Law
    4. None of the above
  46. Which rule does this obey: 1s², 2s², 2pₓ, 2pᵧ?
    1. Pauli’s Exclusion Principle
    2. Hund’s Principle
    3. Aufbau’s Principle
    4. None
  47. What is the angle of see-saw geometry?
    1. 90°
    2. 120°
    3. Both
    4. None
  48. Which is the weakest acid?
    1. HNO₃
    2. H₃PO₄
    3. H₂PO₄⁻
    4. HPO₄²⁻
  49. HOBr + OH⁻ → H₂O + Br⁻. Identify the Brønsted base.
    1. HOBr
    2. OH⁻
    3. H₂O
    4. Br⁻
  50. The shape of hydrogen sulfide is
    1. Trigonal pyramidal
    2. Tetrahedral
    3. Bent
    4. None of the above
  51. The steric number of a molecule having 2 lone pairs and 3 bond pairs is
    1. 3
    2. 2
    3. 5
    4. 1
  52. Which of the following is isoelectronic with Neon?
    1. O²⁻
    2. Mg
    3. Ca
    4. K⁺
  53. Arrange these in order of increasing energy: 4s, 4p, 3d.
    1. 4s < 4p < 3d
    2. 4s < 3d < 4p
    3. 3d < 4s < 4p
    4. 3d < 4p < 4s
  54. Which of the following pairs are isotones?
    1. ¹H and ²H
    2. ²²Ne and ²³Na
    3. ¹⁴C and ¹⁸O
    4. ³²S and ³⁵Cl
  55. When NaHCO₃ is dissolved in water, the resulting solution is
    1. Acidic
    2. Neutral
    3. Basic
    4. None
  56. HF + H₂O → H₃O⁺ + F⁻. What is true about this equation?
    1. HF is the conjugate acid while F⁻ is the base
    2. HF is the base while F⁻ is the conjugate acid
    3. HF is the acid while F⁻ is the conjugate base
    4. HF is the conjugate base while F⁻ is the acid
  57. The energy of an electron in an orbital is always?
    1. Same
    2. Different
    3. Infinite
    4. Zero
  58. Isotopes of an element have
    1. The same chemical properties
    2. Different chemical properties
    3. Both
    4. None
  59. How many lone pairs does the central atom in N₂O have?
    1. 1
    2. 2
    3. 0
    4. 3
  60. In the increasing order, arrange the angles of the geometrical shapes: linear, trigonal planar, tetrahedral, octahedral.
    1. Linear < Tetrahedral < Trigonal planar < Octahedral
    2. Trigonal planar < Octahedral < Tetrahedral < Linear
    3. Tetrahedral < Trigonal planar < Linear < Octahedral
    4. Octahedral < Tetrahedral < Trigonal planar < Linear
  61. In the periodic table, across the period, electronegativity ____
    1. Increases
    2. Decreases
    3. Remains the same
    4. Is constant
  62. What is the correct order of the number of lone pairs for the following: O₃, CO₂, H₂O.
    1. 2, 4, 0
    2. 2, 1, 4
    3. 4, 0, 2
    4. 2, 4, 1
  63. What is the steric number of Boron trifluoride?
    1. 2
    2. 3
    3. 4
    4. 0
  64. According to VSEPR theory, what is the geometry of PH₃?
    1. Trigonal planar
    2. Trigonal bipyramidal
    3. Trigonal pyramidal
    4. Tetrahedral
  65. What then is the bond angle of PH₃?
    1. 107°
    2. 120°
    3. 109.5°
    4. 90°
  66. What is the geometry of CH₄?
    1. Linear
    2. Trigonal planar
    3. V-shaped
    4. Tetrahedral
  67. A gas contains a mixture of 8g oxygen and 14g nitrogen. If the total pressure the gases exert is 750 mmHg, what is the partial pressure of oxygen gas?
    1. 310 mmHg
    2. 250 mmHg
    3. 180 mmHg
    4. 467 mmHg
  68. Which of the following salts is not acidic?
    1. CH₃COONa
    2. NH₄Cl
    3. CuCl₃
    4. CuSO₄
  69. On the periodic table, Boron has lower ionization energy than Beryllium. Why?
    1. 2p orbital has higher energy than 2s orbital
    2. It has a smaller atomic radius
    3. Beryllium is more stable than Boron
    4. None of these
  70. Which of these is amphiprotic?
    1. HCl
    2. NH₃
    3. HF
    4. HCO₃⁻
  71. The mass number of an element is equal to its number of
    1. Protons
    2. Neutrons
    3. Nucleons
    4. Electrons
  72. Which of the following gives the expression for the magnetic quantum number m, in terms of the subsidiary quantum number?
    1. 2l
    2. 2l – 1
    3. l – 2
    4. 2l + 1
  73. The volume of a sample of a gas is 6.0 litres at 35°C and 740 torr, what is its volume at STP?
    1. 6.29 litres
    2. 5.18 litres
    3. 4.37 litres
    4. 3.54 litres
  74. According to Dalton’s law of partial pressure, the total pressure of a gas mixture is equal to the
    1. Difference in partial pressure
    2. Sum of partial pressure
    3. Product of partial pressure
    4. None of the above
  75. Two electrons occupying the same orbital have different
    1. Spin quantum number
    2. Principal quantum number
    3. Azimuthal quantum number
    4. Magnetic quantum number
  76. Which of the following is the strongest acid?
    1. HF
    2. HCl
    3. HBr
    4. HI
  77. What is the molecular geometry of PF₅?
    1. Trigonal pyramidal
    2. Octahedral
    3. Trigonal planar
    4. Trigonal bipyramidal
  78. In the Lewis structure of PF₃, how many lone pairs are on the central atom?
    1. 2
    2. 1
    3. 0
    4. 4
  79. How many valence electrons are in the third shell of Calcium?
    1. 0
    2. 2
    3. 8
    4. 4
  80. Atoms of the same isotopes possess what?
    1. Different neutrons
    2. Same neutrons
    3. Different protons
    4. Same mass
  81. Isobars are
    1. Atoms with the same atomic number but different mass number
    2. Atoms with different atomic number but the same mass number
    3. Atoms with different atomic number and mass number
    4. Atoms with the same atomic structure
  82. Arrange these in the correct order: 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 4p⁶, 4d¹⁰
    1. 1s² < 2s² < 2p⁶ < 3s² < 3p⁶ < 4s² < 4p⁶ < 4d¹⁰
    2. 1s² < 2s² < 2p⁶ < 3s² < 4s² < 3p⁶ < 4p⁶ < 4d¹⁰
    3. 1s² < 2p⁶ < 2s² < 3p⁶ < 3s² < 4s² < 4d¹⁰ < 4p⁶
    4. 1s² < 2s² < 3s² < 3p⁶ < 2p⁶ < 4s² < 4p⁶ < 4d¹⁰
  83. A salt formed from a weak acid and a strong base will give a salt with
    1. pH less than 7
    2. pH greater than 7
    3. Neutral pH
    4. Unstable pH
  84. Hydrolysis refers to
    1. Breaking of bonds by addition of water
    2. Formation of bonds by removal of water
    3. Dissolution of salts in water
    4. Breaking of ions in a solution
  85. The VSEPR theory helps to determine
    1. Shape of molecules
    2. Strength of bonds
    3. Reactivity of elements
    4. Energy of electrons
  86. Which of the following is not true about gas?
    1. Gas has a definite shape
    2. Gas has no definite shape
    3. Gas has a definite volume
    4. Gas fills its container completely
  87. CH₄ has an SN of
    1. 2
    2. 3
    3. 4
    4. 5
  88. The charge-to-mass ratio of positive particles varies with the nature of the
    1. Metal used in the discharge tube
    2. Gas placed in the discharge tube
    3. Both A and B
    4. None of these
  89. According to Brønsted–Lowry, an acid is a
    1. Proton donor
    2. Electron acceptor
    3. Electron donor
    4. Proton acceptor
  90. The f subshell can hold a maximum of how many electrons?
    1. 10
    2. 14
    3. 6
    4. 2
  91. If the number of lone pairs is 0 and there are two atoms bonded to the central atom, what is the SN?
    1. 1
    2. 2
    3. 3
    4. 4
  92. Arrange S, P, D, F in increasing order.
    1. S < P < D < F
    2. F < D < P < S
    3. D < S < P < F
    4. P < F < D < S
  93. Pauli’s Exclusion Principle states that two electrons can occupy the same orbital only if they are
    1. Parallel
    2. Opposite
    3. Random
    4. The same
  94. Heisenberg’s uncertainty principle states that
    1. It is impossible to know both the position and velocity of a particle simultaneously
    2. It is impossible to know both the mass and charge of a particle simultaneously
    3. Electrons always travel in fixed paths
    4. Electrons cannot exist in the nucleus
  95. Which has lower energy between square pyramidal and trigonal bipyramidal?
    1. None
    2. Both
    3. Square pyramidal
    4. Trigonal bipyramidal
  96. What is the geometric shape of water?
    1. Linear
    2. Bent
    3. Trigonal planar
    4. Tetrahedral
  97. What is the shape of silane?
    1. Bent
    2. Tetrahedral
    3. Trigonal planar
    4. Linear
  98. What is the definition of an orbital?
    1. A fixed path of electrons around the nucleus
    2. A region in an atom where the probability of finding an electron is high
    3. The distance between the nucleus and the outermost shell
    4. The energy associated with an electron in an atom
  99. How do I increase the pressure on a gas without increasing the volume?
    1. Increase the temperature
    2. Decrease the number of particles
    3. Increase the container size
    4. Add more gas particles
  100. Calculate the SN of SO₂, a colourless gas that exists as liquid under pressure.
    1. 2
    2. 3
    3. 4
    4. 5

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