General Practical Chemistry I — 2023B Past Questions

University of Ilorin CHM107: 114 questions.

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

1. What is the useful pH range of Murexide?
   1. 8-12
   2. 7.5-10.5
   3. 9-11
   4. 6-13
2. What is the oxidation state of Mn in MnO₂?
   1. -2
   2. +4
   3. +7
   4. +2
3. What is the colour of Eriochrome Black T (EBT) in a sample containing 0.0135 mol/dm³ of Ca²⁺?
   1. Colourless
   2. Blue
   3. Red
   4. Yellow
4. A molecule that forms a covalent bond with a cation or neutral metal atom by donating a pair of electrons is called?
   1. A ligand
   2. A coordinate
   3. A chelate
   4. A complex
5. What is the structure of EDTA?
   1. Hexadentate ligand with four carboxylate and two amine groups
   2. Tetradentate ligand with two carboxylate and two amine groups
   3. Bidentate ligand with one carboxylate and one amine group
   4. Tridentate ligand with three carboxylate groups
6. What is the definition of a ligand?
   1. A molecule that accepts protons
   2. A molecule that donates electron pairs to a metal ion
   3. A molecule that oxidizes metals
   4. A molecule that reduces metals
7. What is used in measuring standard solution?
   1. Volumetric flask
   2. Conical flask
   3. Beaker
   4. Burette
8. What is the pH range of Murexide?
   1. 6-13
   2. 9-11
   3. 7.5-10.5
   4. 8-12
9. Is the solvent always a liquid in a solution?
   1. True
   2. False
   3. Only in aqueous solutions
   4. Depends on the solute
10. What is the full meaning of EDTA?
    1. Ethylenediaminetetraacetic acid
    2. Ethylenedinitrotriacetic acid
    3. Ethylenediaminetriacetic acid
    4. Ethylenediaminediacetic acid
11. All physical measurements have limitations called?
    1. Stability
    2. Instability
    3. Certainty
    4. Uncertainty
12. Mathematical errors in calculation and prejudice are what type of error?
    1. Instrumental
    2. Operator
    3. Indeterminate
    4. Method
13. What are the two phases of crystallization?
    1. Suspension and saturation
    2. Nucleation and particle growth
    3. Co-precipitation and post-precipitation
    4. Occlusion and inclusion
14. Dye indicators are called?
    1. Chrome indicators
    2. Metallochromic
    3. Eriochrome
    4. Solochrome
15. In gravimetric analysis, what is used to calculate the quantity of the species being analyzed?
    1. Titration volume
    2. Precipitate mass
    3. Indicator color change
    4. pH measurement
16. What is the color of Bromocresol green and Bromothymol blue in an acidic medium?
    1. Yellow
    2. Blue
    3. Red
    4. Green
17. The normal distribution curve is also called?
    1. Gaussian
    2. Lagrangian
    3. Caplacian
    4. Cauchus
18. In acid-base titration, the solution in the conical flask is called?
    1. Titrant
    2. Analyte
    3. Titrand
    4. Indicator
19. Methyl orange is used in a titration of NaOH versus HCl. What is the color change?
    1. Yellow to red
    2. Yellow to pink
    3. Pink to yellow
    4. Red to yellow
20. Which theory was based on the ionization of indicators?
    1. Ostwald's theory
    2. Quinoid theory
    3. Lewis theory
    4. Arrhenius theory
21. What is the correct order of steps in chemical analysis?
    1. Sampling, sample preparation, analysis, reporting
    2. Formulating questions, selecting analytical procedure, sampling, sample preparation, analysis, reporting and interpretation of results, drawing conclusions
    3. Sample preparation, analysis, data interpretation, conclusion
    4. Sampling, analysis, validation, reporting
22. What are the phases of crystal growth?
    1. Suspension and saturation
    2. Nucleation and particle growth
    3. Co-precipitation and post-precipitation
    4. Occlusion and inclusion
23. What indicator is used to detect the endpoint in precipitation titration?
    1. pH meter
    2. Methyl orange
    3. Potentiometer
    4. Eriochrome Black T
24. All the following are used for detecting endpoints except?
    1. pH meter
    2. Potentiometer
    3. Hygrometer
    4. Conductometer
25. What is the change in oxidation number of Cr in K₂Cr₂O₇ and Cr₂(SO₃)₂²⁻?
    1. +6 to +2
    2. +6 to +3
    3. +7 to +2
    4. +5 to +3
26. The degree of repeatability is known as?
    1. Precision
    2. Accuracy
    3. Sensitivity
    4. Uncertainty
27. The coloured complex ion used to detect Fe³⁺ is?
    1. Cl⁻
    2. SCN⁻
    3. NO₃⁻
    4. SO₄²⁻
28. Gravimetric titration entails measurement based on?
    1. Volume of titrant
    2. Mass of solute
    3. Color change
    4. pH shift
29. Which indicator cannot be used in NH₄OH and HNO₃ titration?
    1. Methyl orange
    2. Phenolphthalein
    3. Bromothymol blue
    4. Litmus
30. A student uses 10.10 cm³ of 0.01M EDTA to determine Ca²⁺ and Mg²⁺ in 1L water. What is the concentration (in mol/dm³)?
    1. 1.01 × 10⁻⁴
    2. 1.01 × 10⁻³
    3. 1.01 × 10⁻²
    4. 1.01 × 10⁻¹
31. The solution in the conical flask during titration is called?
    1. Titrant
    2. Titrand
    3. Analyte
    4. Base
32. Which type of titration does not employ EDTA?
    1. Complexometric
    2. Redox
    3. Acid-base
    4. Precipitation
33. What is used to determine the endpoint in titrimetric analysis?
    1. Indicator
    2. pH meter
    3. Potentiometer
    4. All of the above
34. What color will red litmus paper turn in potassium hydrogencarbonate (KHCO₃) solution?
    1. Remain red
    2. Turn blue
    3. Turn purple
    4. Turn colorless
35. Phenolphthalein is colorless in which solution?
    1. Neutral (pH 7)
    2. Alkaline (pH > 8.3)
    3. Acidic (pH < 8.3)
    4. Strong acidic solution (pH < 3)
36. A mixture of a weak acid and a strong base will give what solution?
    1. Acidic
    2. Basic
    3. Alkaline
    4. Neutral
37. What is used to standardize EDTA?
    1. NaOH
    2. Primary standard CaCO₃
    3. KMnO₄
    4. HCl
38. Which of these is a compound in the formation of EDTA?
    1. CH₃COONa
    2. NaHCO₃
    3. Na₂H₂Y·2H₂O
    4. Ca-EDTA
39. In titration, endpoint can be determined by change in color by..
    1. Filter paper
    2. Pipette
    3. Burette
    4. Indicator
40. Which of these metals has a low endpoint value in calmagite?
    1. Ca
    2. Mg
    3. Zn
    4. Ni
41. Ammonium chloride in ammonia is what?
    1. Titrant
    2. Titrand
    3. Buffer
    4. Salt
42. Balance the equation: Zn²⁺ + H₂Y²⁻ → ? + 2H⁺
    1. ZnY³⁻
    2. ZnY
    3. ZnY⁻
    4. ZnY²⁻
43. Error found in one side is called?
    1. Random
    2. Systematic
    3. Erratic
    4. Sided
44. The oxidation number of Mn in MnSO₄ is..
    1. +7
    2. +2
    3. +4
    4. -1
45. In the reaction: 2FeCl₃ + SnCl₂ → 2FeCl₂ + SnCl₄, Sn is..
    1. Oxidized
    2. Reduced
    3. Displaced
    4. Complexed
46. First step in ensuring accuracy is through..
    1. Proper calibration
    2. Carefulness
    3. Avoiding error
    4. Proper cleaning
47. Increasing the number of observations helps in improving..
    1. Deviation
    2. Variation
    3. Precision
    4. Error
48. Optimum pH for Mohr titration is?
    1. 7
    2. 8
    3. 6-9
    4. 10
49. What color is Eriochrome Black T when complexed with Cu²⁺?
    1. Blue
    2. Yellow
    3. Red
    4. Green
50. What color are bromothymol green and bromothymol blue in acidic medium?
    1. Green and blue
    2. Yellow and blue
    3. Yellow and yellow
    4. Yellow and green
51. Accuracy can be ensured by:
    1. Carefulness
    2. Calibration of instrument
    3. Both A and B
    4. Neither A nor B
52. Vollhard titration is done in which solution?
    1. H₂SO₄
    2. HCl
    3. NaOH
    4. HNO₃
53. The difference between Endpoint and Equivalence point is?
    1. Endpoint is theoretical, equivalence is experimental
    2. Endpoint is observed, equivalence is stoichiometric
    3. They are identical
    4. Endpoint is pH-dependent, equivalence is not
54. What is the useful pH range for calmagite?
    1. 8-12
    2. 6-13
    3. 7.5-10.5
    4. 9-11
55. Dimercaprol is a:
    1. Masking agent
    2. Demasking agent
    3. Chelating agent
    4. Both A and B
56. 25cm³ of water from Asa dam was titrated using 0.1M EDTA. If it required 15.50cm³ of EDTA to reach endpoint, what is the number of moles of EDTA used?
    1. 1.55 × 10⁻³
    2. 1.55
    3. 15.5 × 10⁻³
    4. 0.155 × 10⁻³
57. Which is widely used in precipitation titration?
    1. BaSO₄
    2. AgNO₃
    3. BaCl₂
    4. AgCl
58. If Ksp value for the titration of a given halide with standard AgNO₃ is small, what happens to the break at equivalence point?
    1. Large
    2. Short
    3. Small
    4. Unrestricted
59. If Mohr's titration is carried out at pH > 10, what will happen?
    1. Ag₂CrO₄ will precipitate
    2. AgOH will precipitate
    3. CrO₄²⁻ will precipitate
    4. HCrO₄⁻ will form
60. Using oxidation number method, what is the valency of C in H₂C₂O₄?
    1. +6, +8
    2. +3, +4
    3. +6, +8
    4. +3, +4
61. Which represents the expression for a REDOX potential?
    1. Ox = Red + ne⁻
    2. Ox – ne⁻ = Red
    3. Ox + ne⁻ = Red
    4. Ox + ne⁻ + H⁺ = Red
62. A solution is supersaturated when?
    1. It contains less solute than equilibrium
    2. It contains exactly saturated solute
    3. It contains more solute than equilibrium
    4. It has no solute
63. In H₂S + Br₂ → 2HBr + S, the oxidant is?
    1. H₂S
    2. Br₂
    3. HBr
    4. S
64. In 2FeCl₃ + SnCl₂ → 2FeCl₂ + SnCl₄, Fe undergoes?
    1. Reduction
    2. Oxidation
    3. Decomposition
    4. Addition
65. Oxidation number can give inaccurate results for valency.
    1. True
    2. False
    3. Cannot Say
    4. Sometimes
66. Shape of normal error curve is?
    1. Bell-shaped
    2. Spiked
    3. Circular
    4. Flat
67. Adsorbent impurities bound to the surface of a crystal are called?
    1. Nucleation and particle growth
    2. Co-precipitation and post-precipitation
    3. Occlusion and inclusion
    4. Suspension and saturation
68. COTI dropped red litmus paper in aqueous K₂CO₃. The color change is?
    1. Red
    2. Orange
    3. Yellow
    4. Blue
69. Dyes used as indicators are called?
    1. Metallochromic
    2. Solochrome
    3. Eriochrome
    4. All of the above
70. Which method uses a chromium salt indicator forming colored compounds with excess titrant?
    1. Volhard
    2. Indirect
    3. Mohr
    4. Argenometric
71. The role of masking and demasking is to?
    1. Improve unselectivity
    2. Improve reactivity
    3. Improve selectivity
    4. Lower reactivity
72. COTI's measurements: 0.0902, 0.0884, 0.0886, 0.1 (accepted: 0.093). Mean? Absolute error? Relative error?
    1. Mean: 0.0918; Abs: 0.0012; Rel: 1.29%
    2. Mean: 0.0900; Abs: 0.0030; Rel: 3.23%
    3. Mean: 0.0910; Abs: 0.0020; Rel: 2.15%
    4. Mean: 0.0920; Abs: 0.0010; Rel: 1.08%
73. Impurities precipitated with desired products even though the solubility of the impurities has not been exceeded is called?
    1. Coprecipitation
    2. Suspended precipitation
    3. Supersaturated
    4. Post-precipitation
74. What is digestion in gravimetric analysis?
    1. Heating the precipitate to remove water
    2. Dissolving the precipitate in acid
    3. Aging the precipitate to improve purity and particle size
    4. Filtering the precipitate quickly
75. How many species should be selectively precipitated in gravimetric analysis for accurate results?
    1. 1
    2. 2
    3. 3
    4. 4
76. How many binding sites are in EDTA?
    1. 6
    2. 4
    3. 2
    4. 8
77. What is the definition of titration?
    1. A technique to measure the volume of a solution
    2. A method to determine concentration by reacting a solution with a standard reagent
    3. A process to purify chemicals
    4. A way to identify unknown substances by color
78. The normal curve graph is associated with?
    1. Standard deviation
    2. Mean deviation
    3. Variance
    4. Mean
79. Which of the following is not a masking agent?
    1. R(SH)₂
    2. HCHO
    3. CH₃CHOCHOH
    4. NaCN
80. Given the demasking reaction: Zn(CN)₄²⁻ + 4HCHO + H₂O → Zn²⁺ + HOCH₂CN + 4OH⁻, what is the demasking agent?
    1. Zn(CN)₄²⁻
    2. HCHO
    3. H₂O
    4. HOCH₂CN
81. The Mohr method is applied in the treatment of?
    1. Drinking water
    2. Domestic water
    3. Industrial water
    4. Waste water
82. The number of equivalents in one liter of solution is called?
    1. Molality
    2. Molarity
    3. Normality
    4. Mole fraction
83. Which method involves the formation of a colored complex and indirect titration?
    1. Mohr method
    2. Volhard method
    3. Fajan method
    4. None
84. Iodimetry is the?
    1. Titration of liberated iodine with thiosulfate
    2. Titration of standard iodine solution
    3. Oxidation of iodide to iodine
    4. Reduction of iodine to iodide
85. Iodometry is the?
    1. Titration of liberated iodine in a reaction
    2. Titration of standard iodine solution
    3. Oxidation of iodide to iodine
    4. Reduction of iodine to iodide
86. In the presence of dilute H₂SO₄, K₂Cr₂O₇ is reduced to Cr₂(SO₄)₃. What is the valency of Cr in K₂Cr₂O₇ and its equivalent weight?
    1. 98
    2. 49
    3. 294
    4. 147
87. When molecules in a solution come together randomly and cause small aggregates, it is called:
    1. Nucleation
    2. Crystal growth
    3. Particle growth
    4. Precipitation
88. Impurities that randomly occupy sites normally occupied by ions that belong in the crystal lattice are called:
    1. Inclusions
    2. Occlusions
    3. Substitutions
    4. Precipitates
89. What is the meaning of peptization?
    1. Breaking down aggregates into colloidal particles
    2. Formation of a precipitate
    3. Crystallization of solutes
    4. Neutralization of charges in a solution
90. Define oxidation and reduction with respect to molecular weight and equivalent weight.
    1. Oxidation: loss of electrons (equivalent weight decreases); Reduction: gain of electrons (equivalent weight increases)
    2. Oxidation: gain of oxygen (equivalent weight remains constant); Reduction: loss of oxygen (equivalent weight remains constant)
    3. Oxidation: increase in oxidation state (equivalent weight varies); Reduction: decrease in oxidation state (equivalent weight varies)
    4. Oxidation: addition of hydrogen (equivalent weight decreases); Reduction: removal of hydrogen (equivalent weight increases)
91. 25 cm³ of water from Asa dam was titrated using 0.1 M EDTA. If it required 15.50 cm³ of EDTA to reach the endpoint, what is the number of moles of EDTA used?
    1. 1.55 × 10⁻³
    2. 1.55
    3. 15.5 × 10⁻³
    4. 0.155 × 10⁻³
92. In the reaction H₂S + Br₂ → 2HBr + S, the oxidant is:
    1. H₂S
    2. Br₂
    3. HBr
    4. S
93. What is the difference between a sequestering and a chelating agent?
    1. Sequestering agents prevent precipitation, while chelating agents form soluble complexes
    2. Sequestering agents remove ions, while chelating agents neutralize them
    3. Sequestering agents are weaker than chelating agents
    4. There is no difference
94. The color of bromocresol green in acid and base, respectively, is:
    1. Red & Blue
    2. Yellow & Blue
    3. Yellow & Yellow
    4. Pink & Blue
95. What is the valency of Cr in K₂Cr₂O₇?
    1. +2
    2. +3
    3. +6
    4. +7
96. How many carboxylate groups will be on a fully deprotonated EDTA?
    1. 2
    2. 4
    3. 6
    4. 8
97. What is the optimum pH for Mohr titration?
    1. 6
    2. 8
    3. 10
    4. 12
98. The reaction between KMnO₄ and oxalic acid in the presence of H₂SO₄ produces:
    1. CO₂ and Mn²⁺
    2. CO and MnO₂
    3. H₂O and MnO₄⁻
    4. H₂ and MnO₂
99. Which of the following is not a type of solution?
    1. True solution
    2. Precipitation
    3. Colloid
    4. Suspension
100. What is the mole ratio of acid to base in the reaction between CH₃COOH and Ba(OH)₂?
     1. 1:1
     2. 2:1
     3. 1:2
     4. 2:2

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