General Practical Chemistry I — 2023A Past Questions

University of Ilorin CHM107: 50 questions.

Topics: Precipitation Titration, Treatment of Analytical Data, Complexometric Titration, Acid-Base Titration, Oxidation-Reduction Titration, Scientific Data and Chemical Experiments

  1. Precipitate must possess one of the following characteristics
    1. Non-readily filterable and washable
    2. Readily filterable and non-washable
    3. Readily filterable and washable
    4. Non-readily filterable and non-washable
  2. The different types of precipitation include the following EXCEPT
    1. Mohr
    2. Fajan
    3. Adsorption
    4. None of the above
  3. The first step in precipitation is the formation of very tiny particles called nuclei. The process is called
    1. Nucleation
    2. Nucleition
    3. Inclusion
    4. Particles of growth
  4. In Mohr titration method, the chloride is titrated with standard AgNO₃ solution using which indicator?
    1. Potassium chromate
    2. Fluorescein
    3. Thiocyanate
    4. Ferric ammonium sulphate
  5. Express 3.00 g/mL multiplied by 1.207 mL to 3 correct significant figures.
    1. 3.620 g
    2. 3.620 g/mL
    3. 3.62 g
    4. 3.62 g/mL
  6. The true volume of a liquid is 2.55 cm³, and the measured volume is 2.58 cm³. Calculate the relative error of the measurements.
    1. 0.012
    2. 0.0012
    3. 0.120
    4. 1.200
  7. The experimental error in which the source is baseless is called
    1. Determinate error
    2. First-class error
    3. Indeterminate error
    4. All of the above
  8. The ideal pH of Mohr titration is
    1. 9.4
    2. 8.9
    3. 10.0
    4. 8.0
  9. What indicator can be best used in titration of H₂SO₄ solution against NH₃ solution?
    1. Methyl orange
    2. Phenolphthalein
    3. Both A & B
    4. None of the above
  10. Errors in calibration are called
    1. Determinate error
    2. Indeterminate error
    3. Both A & B
    4. None of the above
  11. How many significant figures are in 9.8020?
    1. 3
    2. 4
    3. 5
    4. 6
  12. Which of the following is the most suitable indicator for the reaction between CH₃COOH and KOH solution?
    1. Phenolphthalein
    2. Methyl red
    3. Methyl yellow
    4. Methyl orange
  13. EDTA means
    1. Ethylene dinuctide triacetic acid
    2. Ethylene diamide tetraacetic acid
    3. Ethylene diamine tetraacetic acid
    4. Ethylene diamine tetra acetin acid
  14. EDTA is standardized using
    1. NaNO₃
    2. CaCO₃
    3. NH₃
    4. All of the above
  15. What is the change in oxidation number of Cr from K₂Cr₂O₇ to Cr₂O₇²⁻?
    1. +5
    2. -5
    3. +7
    4. -7
  16. When the number of donor groups in a single ligand is 2, it is said to be
    1. Monodentate
    2. Bidentate
    3. Tetradentate
    4. Biligand
  17. A saturated solution of AB₂ contains 8.6×10⁻³ moles AB₂ per liter. Determine the solubility product.
    1. 1.2×10⁻⁷
    2. 3.6×10⁻⁷
    3. 7.4×10⁻⁷
    4. 2.54×10⁻⁷
  18. Indirect determination of [PO₃]³⁻ by precipitating HgCl₂ is an example of
    1. Volatilization method
    2. Precipitation method
    3. Electrogravimetry
    4. Particulate method
  19. How many bonding sites does EDTA have?
    1. 2 bonding sites
    2. 6 bonding sites
    3. 4 bonding sites
    4. 8 bonding sites
  20. What is the useful pH range of Calmagite?
    1. 8.5–11
    2. 9–11
    3. 6–13
    4. 7.5–10.5
  21. Why is buffer added to the solution of titrand during complexometric titration?
    1. To vary the pH of the titrand
    2. To speed up the reaction
    3. To maintain the pH
    4. To make up the titrant
  22. Chemical analysis concerned with how much of a substance is present in a sample is
    1. Quantitative analysis
    2. Qualitative analysis
    3. Volumetric analysis
    4. Theory and practice
  23. The most precise method of quantitative analysis is
    1. Gravimetry
    2. Precipitation
    3. Redox titration
    4. Complexometry
  24. CH₃COOH and NH₄OH... which indicator is used?
    1. Methyl red
    2. Methyl yellow
    3. Phenolphthalein
    4. No suitable indicator
  25. Number of carboxylic groups in EDTA
    1. 2
    2. 3
    3. 4
    4. 6
  26. A 1.963 g sample of an alloy dissolves in nitric acid and diluted to 100 mL. Titrating 25 mL with 0.1078 M KSCN requires 27.19 mL. Calculate the %W/W Silver in the alloy.
    1. 84.4%
    2. 64.4%
    3. 25.6%
    4. 51.2%
  27. Reduction is
    1. Increase in valency and gain of electrons
    2. Decrease in valency and gain of electrons
    3. Increase in valency and loss of electrons
    4. Decrease in valency and loss of electrons
  28. The moisture content of a substance could be gotten using gravimetric method by
    1. Volatilization
    2. Precipitation
    3. Electrogravimetry
    4. Particulate
  29. In precipitation titration, the titration of chloride using adsorption indicator is called?
    1. Volhard’s method
    2. Potentiometric method
    3. Fajan's method
    4. Mohr’s method
  30. Manganese in a 1.52 g sample was precipitated as Mn₃O₄ (FW = 228.8) weighing 0.126 g. Find the percentage of Mn (FW = 54.94) in the sample.
    1. 8.97%
    2. 6.97%
    3. 5.97%
    4. 4.97%
  31. A titre value of 38.8 cm³ of a solution containing 0.4563 g HCl in 250 cm³ was obtained when the acid was titrated against 25.0 cm³ of calcium hydroxide solution. What is the molarity and concentration in g dm⁻³ of the base? (Ca = 40.0, Na = 23, C = 12, O = 16, Cl = 35.5, H = 1.00)
    1. 0.039, 2.21
    2. 0.039, 2.87
    3. 2.87, 0.039
    4. 7.97, 32
  32. The number of significant figures in 0.0030900 and 0.002008 are?
    1. 5 and 6
    2. 4 and 5
    3. 7 and 7
    4. 6 and 4
  33. In the analysis of chromium in three samples of stainless steel, the following results were obtained: A (6.25%, 6.24%, 6.26%), B (6.71%, 6.72%, 6.71%), C (6.05%, 6.57%, 6.32%). Suppose the true value is 6.25%, how precise and accurate are the results?
    1. A, B, C are accurate and precise
    2. Only A is accurate and precise
    3. A and B are accurate and precise
    4. A and C are accurate and precise
  34. A sample of pure potassium chloride was analyzed for chloride ion (Cl⁻) with the following results: 47.24, 47.08, 47.31, 47.42, 47.29, and 47.38. Calculate the standard deviation and percentage relative standard deviation.
    1. 0.19 and 0.40%
    2. 0.12 and 0.25%
    3. 0.13 and 0.27%
    4. 0.15 and 0.30%
  35. Calculate the mean and standard deviation of the following set of analytical results: 15.67 g, 15.69 g, and 16.03 g.
    1. 15.80 and 0.20
    2. 1.580 and 2.0
    3. 15.80 and 2.0
    4. 15.80 and 0.04
  36. Solution A contains 7.000 g H₂SO₄ in 1 dm³, and B is a solution of sodium hydrogen carbonate. If 25 cm³ of B requires 26.9 cm³ of A for complete neutralization, what is the concentration of B in g dm⁻³? (S = 32, Na = 23, H = 1.00, C = 12, O = 16)
    1. 12.752 g dm⁻³
    2. 15.300 g dm⁻³
    3. 12.852 g dm⁻³
    4. 15.400 g dm⁻³
  37. The following requirements must be met for a successful gravimetric determination except:
    1. The desired substance must be completely precipitated
    2. The weighed form of the precipitate should be a stoichiometric compound of known composition
    3. The precipitate must be pure and easily filtered
    4. Nucleation followed particle growth in precipitate formation
  38. The experimental error in which its source cannot be traced is known as:
    1. definite error
    2. Indeterminate or second class error
    3. Determinate error
    4. Systematic error
  39. Completeness of a precipitate reaction is determined by?
    1. the solubility of the precipitate formed
    2. the duration taken for the reaction to occur
    3. the concentrations of the reacting mixtures
    4. the colour of the precipitate formed
  40. In the titration of Silver nitrate with chloride ion during precipitation titration, before the equivalence point we have?
    1. excess Chloride ion
    2. excess of silver ion
    3. equal amount of silver ion and chloride ion
    4. None of the above
  41. What is the value of the gravimetric factor for the conversion of SO₃ to BaSO₄? (Ba = 137, S = 32, O = 16)
    1. 0.3433
    2. 0.2516
    3. 0.4321
    4. 0.2448
  42. An immediate example of redox reaction is:
    1. Displacement
    2. Double decomposition
    3. Electrolysis
    4. Combustion
  43. Errors cannot be completely
    1. Studied
    2. Eliminated
    3. Avoided
    4. Known
  44. Oxidation number gives incorrect value of valency.
    1. True
    2. False
    3. Cannot Say
    4. Sometimes
  45. The closeness of values to the true value is
    1. Accuracy
    2. Precision
    3. Absolute error
    4. Correctness
  46. Precipitating reagent should react with the analyte
    1. Either specifically or, at least selectively to form a precipitate
    2. Neither specifically nor selectively
    3. To give a coloured solution
    4. None of the above
  47. The different types of precipitation titrations include all except
    1. Mohr
    2. Adsorption indicators
    3. Fajans
    4. None of the above
  48. In the Mohr titration, the ideal pH is
    1. 4
    2. 12
    3. 8
    4. 5
  49. The first step in precipitation is the formation of very tiny particles of precipitate called nuclei. The process of forming these particles is called
    1. Nucleation
    2. Nucleation
    3. Nucleation
    4. Nucleation
  50. A is a solution of hydrochloric acid containing 2.92 mol per litre of solution and B is a solution of an impure sodium carbonate. If 25 cm³ of B requires 26.4 cm³ of A using methyl orange indicator, what is the molarity and concentration in g/dm³ of solution B? (Na = 23.0, C = 12.0, O = 16.0, H = 1.0, Cl = 35.5)
    1. 4.48, 0.04
    2. 0.09, 9.54
    3. 0.08, 9.01
    4. 0.04, 4.48

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