General Practical Chemistry I — 2026 Past Questions

University of Ilorin CHM107: 332 questions.

Topics: Oxidation-Reduction Titration, Acid-Base Titration, Complexometric Titration, Precipitation Titration, Treatment of Analytical Data, Basic Glassware and Equipment in the Laboratory, Volumetric Analysis, Scientific Data and Chemical Experiments, General Laboratory Rules and Safety Procedures, Gravimetric Analysis

  1. Which of the following ions can be determined using direct complexometric titration?
    1. Na⁺
    2. Ca²⁺
    3. K⁺
    4. NH₄⁺
  2. The most commonly used titrant in complexometric titration is:
    1. NaOH
    2. KMnO₄
    3. EDTA
    4. HCl
  3. EDTA stands for:
    1. Ethylene diamine tetra acetate
    2. Ethylenediaminetetraacetic acid
    3. Eriochrome diamine tetra acid
    4. Ethyl diamine tetra acetic
  4. The pH of 0.003 M HCl is:
    1. 1.52
    2. 2.52
    3. 3.52
    4. 4.52
  5. If EDTA forms complexes with metal ions of different charges, it is described as:
    1. Reactive
    2. Unreactive
    3. Selective
    4. Non-selective
  6. The oxidation state of carbon in H₂C₂O₄ is:
    1. +2
    2. +3
    3. +4
    4. +6
  7. The most important factor at the break of the titration curve near the equivalence point is the:
    1. Temperature
    2. pH of the solution
    3. Indicator colour
    4. Volume of analyte
  8. The pH of 0.03 M HCl is:
    1. 0.52
    2. 1.52
    3. 2.52
    4. 3.52
  9. The pH of 0.005 M HCl is:
    1. 1.30
    2. 2.30
    3. 3.30
    4. 4.30
  10. The indicator used in iodine titration is:
    1. Methyl orange
    2. Phenolphthalein
    3. Starch
    4. Eriochrome Black T
  11. The complexometric solution commonly used in back titration is:
    1. EDTA
    2. Na₂S₂O₃
    3. KMnO₄
    4. NaOH
  12. The colour of phenolphthalein at pH 3 is:
    1. Pink
    2. Blue
    3. Colourless
    4. Orange
  13. Reducimetric titration involves:
    1. Oxidation reactions
    2. Reduction reactions
    3. Neutralization reactions
    4. Precipitation reactions
  14. A hot plate is used for:
    1. Measuring temperature
    2. Controlled heating of substances
    3. Drying glassware
    4. Filtration
  15. A ligand with two donor atoms is called:
    1. Monodentate
    2. Bidentate
    3. Polydentate
    4. Ambidentate
  16. In iodometry, iodine (I₂) is reduced to:
    1. IO₃⁻
    2. I⁻
    3. I⁺
    4. I₂O₅
  17. Which of the following apparatus is NOT used in titration?
    1. Burette
    2. Pipette
    3. Conical flask
    4. Dropper
  18. Reduction involves:
    1. Loss of electrons and increase in valency
    2. Gain of electrons and decrease in valency
    3. Gain of electrons and increase in valency
    4. Loss of electrons and decrease in valency
  19. The change in oxidation state of carbon when H₂C₂O₄ is converted to CO₂ is:
    1. 0
    2. +1
    3. +2
    4. +4
  20. In Mohr's method, if the pH is greater than 10, the precipitate formed is:
    1. AgCl
    2. Ag₂CrO₄
    3. AgOH
    4. Ag₂SO₄
  21. When red litmus paper is dipped into potassium carbonate solution, it turns:
    1. Red
    2. Blue
    3. Colourless
    4. Yellow
  22. What volume of 0.2 M NaOH is required to prepare 600 cm³ of 0.05 M solution?
    1. 100 cm³
    2. 120 cm³
    3. 150 cm³
    4. 200 cm³
  23. Which of the following is NOT a necessary step in acid–base titration?
    1. Funnel must be removed before titration
    2. The conical flask should be rinsed with the solution it will contain
    3. The burette should be rinsed with the solution it will contain
    4. None of the above
  24. A suitable indicator for titrating H₂SO₄ against Ca(OH)₂ is:
    1. Methyl orange
    2. Phenolphthalein
    3. Starch
    4. Eriochrome Black T
  25. The molar ratio of KOH to H₂SO₄ in their reaction is:
    1. 1:1
    2. 2:1
    3. 1:2
    4. 3:1
  26. Mohr's titration is used for the determination of:
    1. Sulphate ion
    2. Nitrate ion
    3. Chloride ion
    4. Carbonate ion
  27. 0.012345 rounded to three significant figures is:
    1. 0.0123
    2. 0.0124
    3. 0.01235
    4. 0.0120
  28. The oxidation state of carbon in H₂C₂O₄ and its maximum oxidation state are respectively:
    1. +3 and +4
    2. +4 and +6
    3. +3 and +6
    4. +2 and +4
  29. The number of significant figures in 9.00287 is:
    1. 4
    2. 5
    3. 6
    4. 7
  30. In chemical analysis, error can never be totally:
    1. Eliminated
    2. Reduced
    3. Estimated
    4. Measured
  31. Random errors are:
    1. Known errors
    2. Unknown errors
    3. Systematic errors
    4. Constant errors
  32. The closeness of repeated measurements to each other is known as:
    1. Accuracy
    2. Precision
    3. Deviation
    4. Dispersion
  33. In a complexometric titration involving Pb²⁺ and Mg²⁺, NaCN acts as a:
    1. Titrant
    2. Titrand
    3. Demasking agent
    4. Masking agent
  34. In the titration of NaOH with HCl, methyl orange changes colour from:
    1. Red to yellow
    2. Yellow to red
    3. Colourless to pink
    4. Blue to red
  35. How many stepwise ligand additions are involved in the formation of [Fe(CN)₆]³⁻?
    1. 6
    2. 1
    3. 2
    4. 3
  36. Which of the following is a property of hard water?
    1. Costly
    2. Corrosive
    3. Tasteless
    4. Forms scales
  37. Oxidation involves:
    1. Loss of electrons and increase in valency
    2. Loss of electrons and decrease in valency
    3. Gain of electrons and increase in valency
    4. Gain of electrons and decrease in valency
  38. The closeness of a measured value to the true value is called:
    1. Accuracy
    2. Precision
    3. Error
    4. Deviation
  39. Which of the following is used in pipette calibration?
    1. Spectrophotometer
    2. Burette
    3. Analytical balance
    4. Thermometer
  40. Which of the following is a basic salt?
    1. KCl
    2. NH₄Cl
    3. NaNO₃
    4. Na₂CO₃
  41. Which of the following is an example of redox titration?
    1. EDTA titration
    2. Iodometry
    3. Complexometric titration
    4. Acid–base titration
  42. 78.0 has how many significant figures?
    1. 3
    2. 4
    3. 2
    4. 5
  43. The oxidation number of Mn in MnO₂ is:
    1. +2
    2. −2
    3. +4
    4. +7
  44. In acidic medium, MnO₄⁻ is reduced to Mn²⁺. The number of water molecules formed in the balanced equation is:
    1. 4
    2. 6
    3. 8
    4. 2
  45. In the reaction K₂Cr₂O₇ → Cr₂(SO₄)₃, the oxidation state of chromium changes from:
    1. +6 to +3
    2. +12 to +6
    3. +3 to +6
    4. +2 to +3
  46. Bromocresol green is ____ in acidic medium.
    1. Yellow
    2. Blue
    3. Red
    4. Violet
  47. A sequestering agent differs from a chelating agent in that:
    1. Chelating agents form ring complexes
    2. Chelating agents are soluble only in organic solvents
    3. Sequestering agents are soluble in organic solvents
    4. Chelating agents form water-soluble complexes
  48. In the reaction 2FeCl₃ + SnCl₂ → 2FeCl₂ + SnCl₄, the oxidation state of Fe changes from:
    1. +3 to +2
    2. +2 to +3
    3. +3 to +4
    4. +2 to +1
  49. In the reaction 2FeCl₃ + SnCl₂ → 2FeCl₂ + SnCl₄, SnCl₂ acts as a:
    1. Oxidizing agent
    2. Reducing agent
    3. Catalyst
    4. Ligand
  50. Which of the following is NOT a type of EDTA titration?
    1. Direct titration
    2. Back titration
    3. Displacement titration
    4. Blank titration
  51. Which metal ion gives a slow endpoint with Calmagite indicator?
    1. Zn²⁺
    2. Ca²⁺
    3. Mg²⁺
    4. Ni²⁺
  52. The pH of solution in Mohr's titration is usually:
    1. Strongly acidic (1–3)
    2. Slightly alkaline (6–10)
    3. Strongly alkaline (11–14)
    4. Exactly neutral (7 only)
  53. A titration involving silver nitrate is called:
    1. Argentometric titration
    2. Iodometric titration
    3. Complexometric titration
    4. Redox titration
  54. The indicator used in Mohr's titration is:
    1. Methyl orange
    2. Phenolphthalein
    3. Potassium chromate
    4. Bromothymol blue
  55. The use of a watch glass in the laboratory is to:
    1. Measure volume
    2. Evaporate small quantities of liquid
    3. Perform titration
    4. Heat strongly
  56. How many types of indicators are commonly used in precipitation titration?
    1. 1
    2. 2
    3. 3
    4. 4
  57. The process of transferring a proton from acid to base is:
    1. Esterification
    2. Acidification
    3. Neutralization
    4. Transformation
  58. The end point in Mohr's titration is indicated by the formation of:
    1. Reddish-brown Ag₂CrO₄ precipitate
    2. White AgCl precipitate
    3. Yellow AgI precipitate
    4. Green solution
  59. EDTA reacts with a metal ion to form a:
    1. Chelate complex
    2. Simple salt
    3. Precipitate
    4. Oxide
  60. An oxidimetric titration involves:
    1. A reducing agent as titrant
    2. An oxidizing agent as titrant
    3. A base as titrant
    4. A precipitating agent
  61. Oxidimetry generally does not employ chemical indicators.
    1. True
    2. False
    3. Not applicable
    4. Cannot be determined
  62. Why is neutral magnesium added to a buffer complexometrically?
    1. To get a clear precise endpoint
    2. To maintain pH of buffer
    3. To neutralize Ca²⁺ present
    4. To react with EDTA
  63. The number of carboxylic acid groups in EDTA is:
    1. 4
    2. 2
    3. 1
    4. 0
  64. A suitable indicator for titration of a strong acid with a weak base is:
    1. Methyl orange
    2. Phenolphthalein
    3. Starch
    4. Bromothymol blue
  65. KOH is not used as a primary standard because:
    1. It reacts with air
    2. It is a base
    3. It is not pure
    4. It does not dissociate completely in aqueous solution
  66. The pH of 0.001 M HCl solution is:
    1. 3
    2. 6.7
    3. 1
    4. 10
  67. Fajans' method takes place:
    1. On the surface (adsorption) of the precipitate
    2. In the precipitate
    3. In the solution phase
    4. In the filtrate
  68. Laboratory equipment is labelled because:
    1. For proper usage
    2. Proper identification
    3. Safety compliance
    4. Record keeping
  69. Which of the following measures mass with high accuracy?
    1. Top loading balance
    2. Chemical balance
    3. Analytical balance
    4. Beam balance
  70. Oxidation is:
    1. Loss of electron
    2. Gain of electron
    3. Gain of proton
    4. Loss of neutron
  71. Fe²⁺ → Fe³⁺ is oxidation.
    1. True
    2. False
    3. Not applicable
    4. Cannot be determined
  72. Fe²⁺ → Fe³⁺ is reduction.
    1. True
    2. False
    3. Not applicable
    4. Cannot be determined
  73. In the precipitation titration of chloride with AgNO₃, before the equivalence point the pCl is found using:
    1. Precipitated chloride
    2. Precipitated silver nitrate
    3. Excess chloride in solution
    4. Solubility product expression
  74. A crucible in the laboratory is primarily used to:
    1. Hold contents for heating to very high temperatures
    2. Measure liquid volumes accurately
    3. Filter solid from liquid
    4. Store chemicals permanently
  75. What happens in oxidation?
    1. Decrease in valence and loss of electron
    2. Increase in valence and loss of electron
    3. Decrease in valence and gain of electron
    4. Increase in valence and gain of electron
  76. What happens in reduction?
    1. Decrease in valence and loss of electron
    2. Increase in valence and loss of electron
    3. Decrease in valence and gain of electron
    4. Increase in valence and gain of electron
  77. Phenolphthalein in basic and acidic medium is, respectively:
    1. Yellow and pink
    2. Colourless and pink
    3. Pink and colourless
    4. Pink and yellow
  78. When MnO₄⁻ is reduced to Mn²⁺ in acidic medium, how many H⁺ are required and how many water molecules are formed?
    1. 8 and 4
    2. 4 and 8
    3. 6 and 2
    4. 2 and 6
  79. A pipette was calibrated to deliver 10 mL and actually delivers 9.98 mL. Calculate the percentage relative error:
    1. −0.2%
    2. 0.2%
    3. 0.02%
    4. −0.02%
  80. The reactions Fe²⁺ → Fe³⁺ + e⁻ and Sn²⁺ → Sn⁴⁺ + 2e⁻ are reduction reactions.
    1. True
    2. False
    3. Not applicable
    4. Cannot be determined
  81. The colour of thymol blue in acidic solution (pH < 1.2) is:
    1. Yellow
    2. Blue
    3. Red
    4. Green
  82. Which indicator is used for a reaction between weak acid and weak base?
    1. Methyl orange
    2. Phenolphthalein
    3. Bromothymol blue
    4. No suitable indicator
  83. The pH range of methyl orange is:
    1. 1 – 2
    2. 3.1 – 4.4
    3. 6 – 7.6
    4. 8 – 10
  84. Which apparatus is not calibrated?
    1. Beaker
    2. Bunsen burner
    3. Pipette
    4. Burette
  85. The function of Ksp is:
    1. Solubility constant in precipitation
    2. Rate constant
    3. Acid dissociation constant
    4. Oxidation constant
  86. In iodometry, iodine (I₂) is reduced to:
    1. I⁻
    2. IO₃⁻
    3. I₂O₅
    4. I⁺
  87. If iodine reacts with thiosulphate, what is oxidized?
    1. Iodine
    2. Thiosulphate
    3. Iodide
    4. Water
  88. What is the useful pH of Calmagite in complexometric reactions?
    1. 6–13
    2. 7.5–10.5
    3. 9–11
    4. 8–11
  89. Which of the following is correct in electrolysis?
    1. Reduction takes place at the positive electrode
    2. Oxidation takes place at the negative electrode
    3. The negative electrode supplies electrons to the cathode
    4. The negative electrode supplies electrons to the anode
  90. 30 mL delivered from a burette has a mass of 29.94 g. If the density of water is 0.997 g/mL, the error is:
    1. 0.03 mL
    2. 0.06 mL
    3. −0.10 mL
    4. −0.30 mL
  91. In the reaction between potassium permanganate and oxalic acid, which species gains electrons?
    1. MnO₄⁻, oxidant
    2. MnO₄⁻, reductant
    3. CrO₄²⁻, oxidant
    4. CrO₄²⁻, reductant
  92. At what point is the vapour pressure of a liquid equal to the external pressure?
    1. Saturated point
    2. Boiling point
    3. Melting point
    4. Freezing point
  93. In the reaction K₂Cr₂O₇ → Cr₂(SO₄)₃, the change in oxidation state of chromium is:
    1. +6 → +3
    2. +6 → +4
    3. +6 → +2
    4. +6 → 0
  94. What is the function of starch solution in iodine titration?
    1. To act as a buffer
    2. To react with excess iodine
    3. To form a blue-black complex with iodine
    4. To neutralize the solution
  95. In the reactions Mn → Mn²⁺ and Fe²⁺ → Fe³⁺, is there an increase in oxidation state?
    1. True
    2. False
    3. Not applicable
    4. Cannot be determined
  96. A student is expected to wear:
    1. Slippers and flip-flops
    2. Goggles and lab coat
    3. Sandals and apron
    4. Shoes and gloves
  97. Repeating observations in an experiment is mainly to attain:
    1. Precision
    2. Accuracy
    3. Minimize error
    4. Reliability
  98. Variability among measured values is called:
    1. Error
    2. Precision
    3. Accuracy
    4. Deviation
  99. In density determination, the volume of a solid measured in a graduated cylinder is by:
    1. Water displacement
    2. Water elimination
    3. Either A or B
    4. Air displacement
  100. Adsorption indicators exist as:
    1. Ionized form
    2. Unionized form
    3. Neutral form
    4. Combined form

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