General Chemistry I — 2025A Past Questions

University of Ilorin CHM101: 146 questions.

Topics: Hybridisation and shapes of simple molecules, Acids, Bases and Salts, Properties of gases, Atoms, elements, molecules, Electronic configuration, Modern electronic theory of atoms, Periodicity and building up of the periodic table, Chemical bonding and intermolecular forces, Radioactivity, Kinetic theory of matter

  1. The ground state of an atom corresponds to the state of
    1. Maximum energy
    2. Minimum energy
    3. Stable energy
    4. Excited energy
  2. The 2 electrons in the first shell differ in the value of
    1. s
    2. m
    3. n
    4. l
  3. What is the molecular geometry of PF₅?
    1. Trigonal pyramidal
    2. Octahedral
    3. Trigonal planar
    4. Trigonal bipyramidal
  4. In the Lewis structure of PF₃, how many lone pairs are on the central atom?
    1. 2
    2. 1
    3. 0
    4. 4
  5. When sodium bicarbonate dissolves in water, it leads to
    1. Acidic condition
    2. Basic condition
    3. Neutral condition
    4. No change
  6. What is the steric number of boron trifluoride (BF₃)?
    1. 2
    2. 3
    3. 4
    4. 5
  7. What is the steric number of a pair that has 3 atoms bonded to it and 2 lone pairs of electrons?
    1. 3
    2. 4
    3. 5
    4. 6
  8. What does the principal quantum number represent?
    1. Orbital shape
    2. Energy level
    3. Electron spin
    4. Magnetic orientation
  9. How many lone pairs are there on the central atom of SF₄?
    1. 2
    2. 4
    3. 3
    4. 1
  10. What does the azimuthal quantum number represent?
    1. Orbital shape
    2. Energy level
    3. Electron spin
    4. Magnetic orientation
  11. How many valence electrons are in the third shell of calcium?
    1. 0
    2. 2
    3. 8
    4. 4
  12. Atoms with the same isotopes possess what?
    1. Different neutrons
    2. Same neutrons
    3. Different protons
    4. Same mass
  13. Do S₂O, N₂O, and CO₂ have the same arrangement? Identify the odd one out.
    1. S₂O
    2. N₂O
    3. CO₂
    4. None of the above
  14. Under isobars, elements with the same mass number and different atomic numbers are
    1. Correct
    2. Incorrect
    3. Undefined
    4. None of the above
  15. 101 kPa pressure of gas occupies 1 m³ at 303 K. If the temperature increases to 600 K with a constant amount of gas, what will be the new volume of the gas?
    1. 1.98 m³
    2. 2.01 m³
    3. 3.00 m³
    4. 2.45 m³
  16. A salt formed from a weak acid and a strong base will have a
    1. pH less than 7
    2. pH greater than 7
    3. Neutral pH
    4. Unstable pH
  17. 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
  18. The VSEPR theory helps to determine
    1. The shape of molecules
    2. The strength of bonds
    3. The reactivity of elements
    4. The energy levels of electrons
  19. Which of these is not true about gas?
    1. Gas has a definite shape
    2. Gas has no definite shape
    3. Gas has no definite volume
    4. Gas fills its container completely
  20. 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 the above
  21. According to Bronsted-Lowry, an acid is a
    1. Proton donor
    2. Electron acceptor
    3. Proton acceptor
    4. Electron donor
  22. If the number of lone pairs is 0 and there are 2 atoms bonded to the central atom, what is the SN?
    1. 1
    2. 2
    3. 3
    4. 4
  23. Pauli’s exclusion principle states that two electrons can occupy the same orbital only if their direction of spin is:
    1. Parallel
    2. Opposite
    3. Random
    4. The same
  24. Isotopes have ___ atomic number but ____ mass number.
    1. Same, different
    2. Different, same
    3. Same, same
    4. Different, different
  25. Which of the following contains no neutrons?
    1. Protium
    2. Tritium
    3. Deuterium
    4. None of these
  26. The formula PT = P1 + P2 + P3 is derived from:
    1. Charles's Law
    2. Dalton's Law of Partial Pressures
    3. Avogadro's Law
    4. Boyle's Law
  27. Quantum number ‘n’ represents:
    1. Spin of an electron
    2. Shape of the orbital
    3. Energy level or shell
    4. Orientation of the orbital
  28. Which has lower energy between a Square Pyramidal and a Trigonal Bipyramidal geometry?
    1. None
    2. Both
    3. Square Pyramidal
    4. Trigonal Bipyramidal
  29. The energy of an electron in an atomic orbital is always:
    1. Zero
    2. Different
    3. Same
    4. Infinite
  30. The maximum number of electrons that can be accommodated in an orbit is:
    1. 2n
    2. 2n+1
    3. n²
    4. 2n²
  31. What is the steric number and the number of lone pairs on the central atom of boron trifluoride (BF₃)?
    1. 4,1
    2. 0,3
    3. 3,0
    4. 3,1
  32. Find the SN of a molecule having two atoms bonded to the central atom, which has three lone pairs.
    1. 3
    2. 5
    3. 6
    4. 4
  33. What is the geometric shape of water (H₂O)?
    1. Linear
    2. Bent
    3. Trigonal planar
    4. Tetrahedral
  34. Shape of formaldehyde (CH₂O)?
    1. Tetrahedral
    2. Trigonal planar
    3. Linear
    4. Bent
  35. Shape of silane (SiH₄)?
    1. Bent
    2. Tetrahedral
    3. Trigonal planar
    4. Linear
  36. How to increase the pressure on a gas without increasing the volume?
    1. Increase temperature
    2. Decrease the number of particles
    3. Increase the container size
    4. Add more gas particles
  37. Calculate the steric number of SO₂, a colorless gas that exists as a liquid under pressure:
    1. 2
    2. 3
    3. 4
    4. 5
  38. Calculate the steric number of H₂O and determine the H-O-H angle:
    1. 3, 120°
    2. 4, 109.5°
    3. 5, 60.5°
    4. 2, 180°
  39. What is the property of an element that is a whole number?
    1. Atomic radius
    2. Atomic number
    3. Atomic volume
    4. Atomic mass
  40. If the value of Azimuthal Q.N (l) is 2, how many values are there for magnetic Q.N (m)?
    1. 3
    2. 4
    3. 5
    4. 2
  41. Which one has lower energy between Square Pyramidal and Trigonal Pyramidal?
    1. None
    2. Both
    3. Square Pyramidal
    4. Trigonal Pyramidal
  42. What is the bond angle for a molecule with a trigonal pyramidal geometry?
    1. 120°
    2. 180°
    3. 90°
    4. 109.5°
  43. What is the steric number of a molecule with 3 atoms bonded to the central atom and 2 lone pairs?
    1. 5
    2. 3
    3. 4
    4. 2
  44. What property is responsible for the strong reaction of acids?
    1. Strong ionization
    2. Concentration
    3. Molecular size
    4. Density
  45. Which is the strongest?
    1. HClO
    2. HClO₂
    3. HClO₃
    4. HClO₄
  46. Which gas is produced when metals react with acids?
    1. Oxygen
    2. Hydrogen
    3. Carbon dioxide
    4. Nitrogen
  47. What is the pH of a neutral solution at 25°C?
    1. 0
    2. 7
    3. 14
    4. 10
  48. Which equation represents an ideal gas?
    1. PV = nRT
    2. P + R = nT
    3. PV = RT
    4. V/T = P/n
  49. Two nuclei, A and B, have the same mass number of 15 and 16, respectively. If the number of protons in A is 7, what is the number of protons in B?
    1. 6
    2. 5
    3. 8
    4. 9
  50. Convert 760 mmHg to ATM.
    1. 0.5 ATM
    2. 1 ATM
    3. 2 ATM
    4. 1.5 ATM
  51. Which of the following has different atomic numbers but the same number of neutrons?
    1. Isomers
    2. Isotones
    3. Isobars
    4. Isotopes
  52. Carbon(IV) oxide during photosynthesis has what shape?
    1. Linear
    2. Tetrahedral
    3. Trigonal pyramidal
    4. Octahedral
  53. SO₂ has how many lone pairs?
    1. 0
    2. 1
    3. 2
    4. 3
  54. Why is pressure exerted by gases on the walls of the container in all directions?
    1. Random motion of gas molecules
    2. Constant volume
    3. Temperature uniformity
    4. Molecular bonds
  55. The H-C-H bond angle in methane is:
    1. 90°
    2. 109.5°
    3. 120°
    4. 180°
  56. Which of the following have the same molecular geometry: CO₂, O₃, SO₂?
    1. CO₂ and O₃
    2. CO₂ and SO₂
    3. O₃ and SO₂
    4. None
  57. When nitric acid reacts with KOH, what salt is formed?
    1. Potassium nitrate
    2. Sodium nitrate
    3. Potassium hydroxide
    4. Ammonium nitrate
  58. Arrange in order of increasing acidic strength: HClO₄, HOClO₃, HOClO₂, HOCl.
    1. HOCl < HOClO₂ < HOClO₃ < HClO₄
    2. HClO₄ < HOClO₃ < HOClO₂ < HOCl
    3. HOClO₃ < HOCl < HOClO₂ < HClO₄
    4. HOCl < HClO₄ < HOClO₂ < HOClO₃
  59. Who proposed stationary orbits?
    1. Rutherford
    2. Bohr
    3. Planck
    4. Dalton
  60. The second electron affinity is always:
    1. Positive
    2. Negative
    3. Neutral
    4. Zero
  61. What is the unit for electron affinity?
    1. Joules per mole
    2. Kilojoules
    3. Coulombs
    4. Volts
  62. Which of the following is not an acidic salt?
    1. CH₃COONa
    2. NaHSO₄
    3. KHS
    4. Na₂SO₄
  63. The conversion of a solid directly to a gaseous form is called:
    1. Sublimation
    2. Evaporation
    3. Condensation
    4. Deposition
  64. What is the steric number of BF₃ and how many lone pairs does it have?
    1. 4, 2
    2. 3, 1
    3. 3, 0
    4. 4, 0
  65. What is the steric number for NH₃?
    1. 3
    2. 4
    3. 2
    4. 5
  66. What is the accepted formula for hydrogen in acid?
    1. H⁺
    2. H₃O⁺
    3. H₂⁺
    4. H₄O⁺
  67. What are the correct steps for determining molecular geometry? I. Define the substance molecular geometry II. Determine the steric number III. Draw the Lewis structure IV. Determine the shape
    1. IV, III, I, II
    2. IV, I, II, III
    3. III, II, I, IV
    4. I, II, III, IV
  68. What quantum number explains the shape of atomic orbitals?
    1. Principal quantum number (n)
    2. Azimuthal quantum number (l)
    3. Magnetic quantum number (m)
    4. Spin quantum number (s)
  69. What is the steric number and number of lone pairs in H₂O?
    1. 3; 2
    2. 4; 3
    3. 4; 2
    4. 2; 4
  70. ______ is used to describe atoms with the same mass number but different atomic numbers.
    1. Isotopes
    2. Isotones
    3. Isobars
    4. Isoelectronic
  71. Which one has the lowest energy between trigonal bipyramidal and square planar?
    1. Trigonal bipyramidal
    2. Square planar
    3. Both have the same energy
    4. None of the above
  72. What is the azimuthal quantum number (l) for the last electron in nitrogen (N)?
    1. 0
    2. 3
    3. 1
    4. 2
  73. What is the steric number and lone pair electrons of N₂O?
    1. 1, 3
    2. 0, 3
    3. 3, 1
    4. 3, 0
  74. If a gas has a volume of 6.982 L and pressure of 8.532 atm at 20.20°C, what is the new temperature when the pressure increases to 10.406 atm (assuming constant volume)?
    1. 24.6°C
    2. 89.4°C
    3. 32.8°C
    4. None of the above
  75. What is the unit of electron affinity?
    1. g/mol
    2. kJ/mol
    3. J/mol
    4. kg/mol
  76. What is the lone pair electron and steric number in BF₃?
    1. 1, 3
    2. 0, 3
    3. 3, 1
    4. 2, 4
  77. The sodium atom has M = 23 and P = 11. What is the neutron number?
    1. It is less than the proton number
    2. It is equal to the number of protons
    3. No option
    4. The neutron number is greater than the proton number
  78. How many lone pairs does N₂O have?
    1. 0
    2. 1
    3. 2
    4. 3
  79. What is the molecular geometry of CO₂, NO₂, and H₂O?
    1. Linear, Bent, Trigonal planar
    2. Linear, Bent, Bent
    3. Bent, Linear, Linear
    4. Linear, Linear, Bent
  80. What is the shape of CO₂?
    1. Linear
    2. Bent
    3. Trigonal planar
    4. Tetrahedral
  81. Acid-base theory includes all except:
    1. Lewis
    2. Dalton
    3. Arrhenius
    4. Bronsted-Lowry
  82. Which energy level is increasing: 4s, 3d, 4p?
    1. 4s < 3d < 4p
    2. 3d < 4s < 4p
    3. 4p < 4s < 3d
    4. 3d < 4p < 4s
  83. Modern replacement of the acid definition:
    1. H₃O⁺
    2. H⁺
    3. H₂O⁺
    4. OH⁻
  84. What are alkalis?
    1. Acids that aren't soluble in water
    2. Bases that aren't soluble in water
    3. Acids that are soluble in water
    4. Bases that are soluble in water
  85. What is the sum of the last electron of a lithium atom?
    1. 2
    2. 5/2
    3. 3
    4. 3/2
  86. The total pressure of the mixture of 8.0 g of oxygen and 14 g of nitrogen in a container is 750 mmHg. What is the pressure of oxygen?
    1. 125 mmHg
    2. 135 mmHg
    3. 500 mmHg
    4. 250 mmHg
  87. What is the conjugate base of HClO₄?
    1. ClO₄⁻
    2. HClO₄
    3. Cl⁻
    4. OH⁻
  88. Examples of strong acids?
    1. HCl, H₂SO₄, HNO₃
    2. H₂CO₃, HClO₄, H₃PO₄
    3. H₂S, HF, HNO₂
    4. NH₃, H₂SO₃, HCl
  89. If the temperature is kept constant, what is required to increase the pressure of gas in a container?
    1. Increase the volume
    2. Decrease the volume
    3. Add more gas molecules
    4. Both B and C
  90. In the Lewis structure of PF₃, how many lone pairs are on the central atom?
    1. 2
    2. 0
    3. 1
    4. 4
  91. Which of these is the correct molecular geometry of silane (SiH₄)?
    1. Octahedral
    2. Seesaw
    3. Tetrahedral
    4. Bent
  92. What are the steric number and the number of lone pairs on the central atom of boron trifluoride (BF₃)?
    1. 3, 1
    2. 4, 1
    3. 3, 0
    4. 0, 3
  93. Which of the following pairs are isobars?
    1. ¹⁴C and ¹⁴N
    2. ⁴⁰Ca and ⁴⁰Ar
    3. ³⁹K and ⁴⁰Ca
    4. ¹⁶O and ¹⁸O
  94. Which of the following pairs are isotones?
    1. ¹⁴C and ¹⁴N
    2. ¹⁵N and ¹⁶O
    3. ⁴⁰Ca and ⁴⁰Ar
    4. ³⁹K and ⁴⁰Ca
  95. The electron affinity of an atom ______ across a period.
    1. Decreases
    2. Increases
    3. Remains constant
    4. Oscillates
  96. What would be the nature of the resulting solution when NaHCO₃ is dissolved in water?
    1. Acidic
    2. Basic
    3. Neutral
    4. Amphoteric
  97. Why does CO₂ have a linear geometry while SO₂ is bent?
    1. CO₂ has no lone pairs on the central atom, while SO₂ does
    2. CO₂ has double bonds, while SO₂ has single bonds
    3. CO₂ has a smaller steric number than SO₂
    4. CO₂ forms tetrahedral bonds, while SO₂ forms trigonal planar bonds
  98. What is the steric number of boron trifluoride?
    1. 3
    2. 4
    3. 2
    4. 5
  99. What are the steric number and bond angle of H₂O?
    1. 3, 104.5°
    2. 4, 109.5°
    3. 2, 180°
    4. 4, 120°
  100. What would be the geometry of a compound where the central atom has two atoms bonded to it and three lone pairs?
    1. Linear
    2. Tetrahedral
    3. Trigonal bipyramidal
    4. Bent

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