General Practical Chemistry I — 2020 Past Questions

University of Ilorin CHM107: 37 questions.

Topics: Precipitation Titration, Oxidation-Reduction Titration, Volumetric Analysis, Treatment of Analytical Data, Acid-Base Titration, Scientific Data and Chemical Experiments, General Laboratory Rules and Safety Procedures

  1. Which of the following is not a bidentate ligand?
    1. Thiocyanato
    2. Ethylene diamine
    3. Oxalato
    4. Glycine
  2. A 1.963g sample of an alloy dissolves in nitric acid and diluted to volume in a 100ml volumetric flask. Titrating a 25ml portion with a 0.1078M KSCN requires 27.19ml to reach the end point. Calculate the %W/W Silver in the alloy.
    1. 84.4%
    2. 64.4%
    3. 25.6%
    4. 32.3%
  3. Which of the following is the odd one out?
    1. Lewis Base
    2. Electrophile
    3. Nucleophile
    4. Ligand
  4. The %W/W of Ag in a sample of an alloy of unknown mass dissolved in nitric acid and diluted to volume in a 100ml volumetric flask was determined to be 64.4%. Titrating a 25ml portion with a 0.1078M KSCN requires 27.19ml to reach the end point. Calculate the mass of the sample in mg.
    1. 196mg
    2. 1960mg
    3. 1096mg
    4. 1.96mg
  5. 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
  6. During a typical acid-base titration, what colour does methyl orange have in the basic medium?
    1. Red
    2. Orange
    3. Yellow
    4. Blue
  7. What is oxine?
    1. 2-hydroquinone
    2. 2-hydroxoquinone
    3. 4-hydroxoquinone
    4. 8-hydroxyquinoline
  8. Which of these indicators can be used for a weak acid and a weak base?
    1. Methyl orange and phenolphthalein
    2. Methyl red and methyl orange
    3. Phenolphthalein and methyl red
    4. No suitable indicator
  9. Random errors are
    1. Avoidable
    2. Unavoidable
    3. Intentional
    4. Deliberate
  10. Which of these pair compounds have the same oxidation states with that of common elements?
    1. SO₃/H₂SO₄
    2. K₂Cr₂O₇ & Cr(OH)₃
    3. CO & CO₂
    4. FeO & Fe₂O₃
  11. The titrant mostly used in precipitation titration is
    1. AgNO₃
    2. KSCN
    3. FeSCN
    4. AgCl
  12. 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
  13. Indicator commonly used for potassium permanganate titration is?
    1. Redox indicator
    2. Self-indicator
    3. Starch indicator
    4. Couple indicator
  14. To choose a suitable indicator for acid-base titration, it depends on?
    1. The basicity of acid and base
    2. The molarity of acid and base
    3. The molality of acid and base
    4. Strength of acid and base
  15. What indicator is used when using K₂Cr₂O₇ in redox titration?
    1. KMnO₄
    2. Diphenylamine
    3. Starch
    4. Triphenylamine
  16. 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
  17. Mohr’s method is not used in acidic medium because
    1. The chromate ion is protonated to chromic acid
    2. The brown color of silver hydroxide interferes with the reaction
    3. Silver chromate precipitates prematurely
    4. The indicator decomposes
  18. NiSO₄ reacts with which of these ions using I⁻ ion indicator to form a complex?
    1. Cl⁻
    2. F⁻
    3. CN⁻
    4. SCN⁻
  19. What is the colour of methyl orange at a pH of 12?
    1. Red
    2. Yellow
    3. Orange
    4. Blue
  20. What forms the secondary layer in Fajan’s precipitation?
    1. Difluorescein
    2. Silver-difluorescein
    3. Chloride ion
    4. Adsorbed water
  21. EDTA is
    1. Hexadentate
    2. Tridentate
    3. Bidentate
    4. Monodentate
  22. Which is not a type of gravimetric analysis?
    1. Electronic gravimetry
    2. Volatilization gravimetry
    3. Particulate gravimetry
    4. Precipitation gravimetry
  23. Which of these is bidentate?
    1. Ammine
    2. Oxalato
    3. Thiocyanato
    4. Cyanide
  24. What is the real and calculated oxidation number of carbon in H₂C₂O₄ respectively?
    1. +4 and +3
    2. +2 and +3
    3. +3 and +4
    4. +3 and +2
  25. Which of the following indicators has a yellow colour at pH of 10?
    1. Bromocresol green
    2. Phenol red
    3. Thymol blue
    4. Alizarin yellow
  26. Which of these types of chemical reactions is NOT a redox reaction?
    1. Decomposition
    2. Single replacement
    3. Double replacement
    4. Combustion
  27. Which of the following methods is used in a basic medium?
    1. Mohr's
    2. Volhard's
    3. Fajan's
    4. None of the above
  28. An immediate example of redox reaction is
    1. Displacement
    2. Double decomposition
    3. Electrolysis
    4. Neutralization
  29. The following measurements were obtained for a metal bar: 4.012g, 4.022g, 4.019g, 4.011g, 4.017g, 4.018g and 4.024g. Calculate the mean.
    1. 4.0175g
    2. 4.018g
    3. 4.01757g
    4. 4.017g
  30. A sample of water has a mass of 234.9g at 25°C. What is the volume of the water in cubic meters, given that the density of water at 25°C is 0.99707g/ml?
    1. 235.590m³
    2. 236.6m³
    3. 0.0002356m³
    4. 0.0023559m³
  31. In a reaction between KMnO₄ producing MnSO₄, what's the oxidation number of Mn in KMnO₄ and the equivalent weight?
    1. 7 & 55
    2. 7 & 22
    3. 5 & 55
    4. 5 & 22
  32. In an oxide X, molecular mass is 110, find the compound X when 29.1% of the compound is oxygen and atomic mass of X is 39.
    1. X₂O₂
    2. XO₂
    3. X₂O
    4. XO
  33. In the titration of Br⁻, which titrant(s) is/are used?
    1. AgNO₃
    2. AgNO₃, KSCN
    3. KSCN
    4. AgNO₃ & AgNO₃, KSCN
  34. The moisture content of a substance could be gotten using gravimetric method by
    1. Volatilization
    2. Precipitation
    3. Electrogravimetry
    4. Particulate
  35. For complexometric titration, how is the concentration of the ligand calculated when given the concentration of EDTA and alpha value?
    1. [Y⁴⁻] = α × [EDTA]
    2. [Y⁴⁻] = [EDTA] / α
    3. [Y⁴⁻] = α + [EDTA]
    4. [Y⁴⁻] = α - [EDTA]
  36. What is the correct expression for Solubility Product (Ksp)?
    1. Ksp = [A⁺]ᵃ[B⁻]ᵇ
    2. Ksp = [A⁺] + [B⁻]
    3. Ksp = [A⁺] / [B⁻]
    4. Ksp = [A⁺]ᵃ - [B⁻]ᵇ
  37. In the titration of Br⁻, which titrant(s) is/are used?
    1. AgNO₃
    2. AgNO₃, KSCN
    3. KSCN
    4. AgNO₃ & AgNO₃, KSCN

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