analytical chemistry mc questions

HKDSE Chemistry A Modern View Part XV Analytical Chemistry

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Multiple Choice Questions

Section 63.1

1. Which of the following combinations concerning an ion in aqueous solution and its

corresponding colour is correct?

Ion Colour

A. Copper(II) ion Green

B. Dichromate ion Orange

C. Iron(II) ion Yellow

D. Permanganate ion Very pale pink

Section 63.2

2. What is the flame colour of potassium chloride when it is heated in a Bunsen flame?

A. Brick-red

B. Bluish green

C. White

D. Lilac

Section 63.3

3. Which of the following hydroxides can dissolve in excess ammonia solution?

(1) Zinc hydroxide

(2) Aluminium hydroxide

(3) Copper(II) hydroxide

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

4. Which of the following statements concerning copper(II) compounds are correct?

(1) Copper(II) hydroxide can dissolve in excess ammonia solution.

(2) Copper(II) hydroxide cannot dissolve in excess sodium hydroxide solution.

(3) Copper(II) compounds will give bluish green flame when heated in Bunsen flame.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)


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5. Which of the following compounds does NOT form a precipitate with excess ammonia

solution?

A. Iron(II) chloride

B. Magnesium nitrate

C. Copper(II) sulphate

D. Aluminium iodide

Section 63.4

6. What would be observed when potassium carbonate is heated?

A. A brick-red flame is observed

B. A black solid is formed.

C. A gas which turns limewater milky is evolved.

D. No observable change.

7. Which of the following acids can be used to acidify silver nitrate solution for the test of

halides?

A. Hydrochloric acid

B. Dilute nitric acid

C. Sulphuric acid

D. Carbonic acid

8. Which of the following statements concerning hypochlorite ions are INCORRECT?

A. They are the main ingredient of the bleach.

B. They have the oxidizing power.

C. They turn moist blue litmus paper red.

D. They react with hydrochloric acid to give chlorine gas.

9. Which of the following tests can be used to distinguish between a solution containing

hypochlorite ions and a solution containing sulphite ions?

(1) Adding silver nitrate solution to the solutions.

(2) Adding dilute hydrochloric acid to the solutions.

(3) Testing the solutions with moist litmus paper.

A. (1) only

B. (2) only

C. (1) and (3) only

D. (2) and (3) only


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10. Which of the following substances does NOT form a precipitate with silver ions?

A. Hydrochloric acid

B. Sulphuric acid

C. Potassium nitrate

D. Sodium bromide

Section 63.5

11. Which of the following statements is INCORRECT?

A. When acidified silver nitrate solution is added to sodium iodide solution, a

yellow precipitate will form.

B. When a little ammonia solution is added to iron(II) nitrate solution, a dirty green

precipitate will form. C. When aqueous sulphur dioxide is added to acidified potassium permanganate

solution, the solution will be decolorized.

D. When but-2-ene is added to acidified potassium dichromate solution, the

solution will change from orange to green.

12. Which of the following substances is odourless?

A. Ammonia solution

B. Hydrogen sulphide

C. Sulphur dioxide

D. Carbon dioxdie

13. Which of following gases gives a characteristic smell?

A. Carbon dioxide

B. Oxygen

C. Hydrogen

D. Sulphur dioxide

14. Which of the following statements concerning ammonia is/are correct?

(1) It turns acidified potassium dichromate solution from orange to green.

(2) It forms a white fume with hydrogen chloride.

(3) It turns dry red litmus paper blue.

A. (1) only

B. (2) only

C. (1) and (3) only

D. (2) and (3) only


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15. Which of the following gases will turn the colour of moist litmus paper when

dissolving in water?

(1) Hydrogen chloride

(2) Ammonia

(3) Sulphur dioxide

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

16. Which of the following statements concerning sulphur dioxide are correct?

(1) The reaction between aqueous sulphur dioxide and bromine water is a redox reaction.

(2) Aqueous sulphur dioxide could bleach moist litmus paper.

(3) It is one of the air pollutants which cause acid rain.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

Section 63.6

17. Which of the following tests show observable colour change?

(1) Test propene with bromine which is dissolved in 1,1,1-trichloromethane.

(2) Test propene with acidified potassium permanganate solution.

(3) Test propene with acidified potassium dichromate solution.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)


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18. Which of the following observations is INCORRECT?

A. Brick-red flame is observed when a calcium compound is heated in a Bunsen

flame.

B. A silver mirror is observed when propanone is warmed with Tollens’ reagent in a

hot water bath.

C. A white fume is observed when hydrogen chloride gas is placed near ammonia

gas.

D. A choking smell of burning sulphur is detected after adding dilute hydrochloric

acid to iron(II) sulphite solution.

19. When an organic compound X is added to acidified potassium dichromate solution, a

colour change is observed. Then the resultant solution is heated with ethanol in the

presence of an acid, a characteristic pleasant fruity smell is detected.

Which of the following statements are correct?

(1) Compound X can be a primary alcohol.

(2) Acidified potassium dichromate solution is decolorized.

(3) The acid should be concentrated sulphuric acid.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

20. Which of the following test(s) is/are used to distinguish between alkanes and alkenes?

(1) Reacting with bromine in shade

(2) Reacting with acidified potassium dichromate solution

(3) Reacting with 2,4-dinitrophenylhydrazine

A. (1) only

B. (2) only

C. (1) and (3) only

D. (2) and (3) only

21. Which of the following reagents can be used to distinguish between alkenes and

primary alcohols?

(1) Acidified potassium permanganate solution

(2) Acidified potassium dichromate solution

(3) Hydrogen chloride

A. (1) only

B. (2) only


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C. (1) and (3) only

D. (2) and (3) only

22. Which of the following statements concerning Tollens’ reagents are correct?

(1) It can be used to distinguish between an aldehyde and a ketone.

(2) It is a solution of silver nitrate in excess ammonia solution.

(3) It contains the diamminesilver(I) ion in an alkaline solution.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

23. Substance X is an organic compound. It could decolorize acidified potassium

permanganate solution and turn acidified potassium dichromate solution from orange to

green.

Which of the following functional groups is/are more likely to be present in substance X?

(1) Hydroxyl group

(2) Carbon-carbon double bond

(3) Carboxyl group

A. (1) only

B. (2) only

C. (1) and (3) only

D. (2) and (3) only

Section 63.7

24. The following tests were carried out to identify two unknown anions in a sample of

solution and the solution was divided into three portions.

Test Observation

(1) Add acidified AgNO3(aq) to the

first portion

No precipitate forms

(2) Add the second portion to

acidified K2Cr2O7(aq)

Acidified K2Cr2O7(aq) changed from

orange to green

(3) Add a drop of solution from the

third portion to a piece of moist

litmus paper

The moist litmus paper turned white

The two unknown anions should be:

A. Cl and CO32


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B. Br and SO32

C. CO32 and ClO

D. SO32 and ClO

25. The following tests were carried out to identify three unknown cations in a sample of

solution and the solution was divided into three portions:

Test Observation

(1) Add NH3(aq) to the first

portion

Dirty green precipitate formed

(2) Perform flame test on the

second portion

Golden yellow flame could be observed

(3) Add NaOH(aq) to the third

portion and warm the mixture

A gas which turns moist red litmus paper

blue was evolved

The three unknown cations should be:

A. Mg2+, Ca2+ and Al3+

B. Cu2+, Ca2+ and Al3+

C. Fe2+, Na+ and NH4+

D. Fe3+, Na+ and NH4+

Section 63.8

26. Which of the following hazard warning labels are shown on the reagent bottle of

benzene?

(1) Oxidizing

(2) Carcinogenic

(3) Flammable

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

Sections 64.164.2

27. Some lead(II) oxide is contaminated with a little magnesium chloride. How do we

remove magnesium chloride from the mixture?

A. Add dilute acid to the mixture and then filter.

B. Heat the mixture and then cool to room temperature.

C. Add water to the mixture and then filter.

D. Add water to the mixture and then cool to room temperature.


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28. Which of the following statements concerning crystallization are correct?

(1) Crystals obtained by slow cooling are more pure than those obtained quickly.

(2) After filtration, we should use a large amount of distilled water to wash the crystals in

order to remove any soluble impurities.

(3) Crystallization is a physical method that separates a dissolved solute from its

solution.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

Section 64.3

29. Which of the following substances CANNOT be separated by distillation?

A. A mixture of proteins

B. Crude oil fractions

C. Oxygen and nitrogen in air

D. Water in salt solution

Section 64.4

30. Which of the following mixtures can be separated by solvent extraction?

(1) KCl(aq) and NaCl(aq)

(2) Hexane and propan-2-ol

(3) Ethanol and water

A. (1) only

B. (2) only

C. (1) and (3) only

D. (2) and (3) only

31. Which of the following methods is the most suitable to obtain magnesium sulphate

crystal from water?

A. Simple distillation

B. Crystallization

C. Fractional distillation

D. Solvent extraction


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32. Hexane and water can be separated by a separating funnel. Which of the following

correctly explains why this separation method works?

A. Hexane and water have different boiling points.

B. Hexane and water have different densities.

C. Hexane and water have different relative molecular masses.

D. Hexane and water do not mix.

33. After shaking the separating funnel, we should invert it and open the tap.

Which of the following statements is the purpose for the above procedure?

A. To extract the desired substances more efficiently.

B. To mix the two solvent layers by air.

C. To get rid of the impurities.

D. To release the pressure.

34. Which of the following statements concerning liquid-liquid extraction are correct?

(1) It involves the use of a separating funnel.

(2) It is used to separate two liquids which are miscible.

(3) It is a physical method.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

Section 64.5

35. Which of the following statements about chromatography is INCORRECT?

A. Alumina and silica gel are commonly packed in the vertical glass column in

column chromatography.

B. The substances with different Rf values are considered as different compounds.

C. The component substances are separated according to their different solubilities

in the solvent.

D. In paper chromatography, a pen is used for drawing the baseline.

36. There is a mixture of dye A, dye B, dye C and dye D. It is known that two of the dyes

are the same.

After performing paper chromatography, the following results were obtained.

A red spot from dye A travelled 7 cm from the baseline.

A red spot from dye B travelled 8 cm from the baseline.

A yellow spot from dye C travelled 7 cm from the baseline.


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A red spot from dye D travelled 7 cm from the baseline.

The distance travelled by the solvent is 10 cm.

Which of the following statements is INCORRECT?

A. The Rf value of the red spot from dye A is 0.7.

B. The Rf value of the red spot from dye B is 0.8.

C. Dye A and dye C are the same because their spots have the same Rf value.

D. Dye A and dye D are the same because their spots have the same Rf value.

37. Which of the following statements about chromatography is INCORRECT?

A. Silica gel is used to be coated onto the plates for thin-layer chromatography.

B. The Rf value compares the distance travelled by a component substance to that

travelled by the solvent.

C. Every component in a mixture can be separated by using chromatography.

D. Column chromatography can separate different solutes in a mixture for further

use.

38. Which of the following methods is the most suitable to increase the concentration of

ethanol in wines?

A. Crystallization

B. Chromatography

C. Liquid-liquid extraction

D. Fractional distillation

39. Four coloured substances were spotted on a piece of filter paper, which was then

suspended in an alcohol-water mixture. The four coloured substances include dye A, and

three basic dyes red, blue and green. After some time, the following chromatogram was

obtained.

What colour does dye A contain?

A Red(1)

Blue(2)

Green(3)


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A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

40. Which of the following statements concerning chromatography are correct?

(1) Paper chromatography and thin-layer chromatography are applied for identification

of different solutes in a solution.

(2) Column chromatography is applied for separation of different substances in a mixture

rather than for identification.

(3) Chromatography is a type of physical methods.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

41. Which of the following statements concerning thin-layer chromatography are correct?

(1) It is about three times faster than paper chromatography.

(2) It can work with very small amounts of samples.

(3) It is mainly used for the separation of organic compounds.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

Section 64.6

42. Which of the following methods can be used for the test for purity?

(1) Determination of boiling points of liquids

(2) Determination of melting points of solids

(3) Flame test

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)


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43. Which of the following properties shows that a solid is pure?

A. The solid is colourless.

B. The solid melts completely.

C. The solid does not turn the colour of dry cobalt(II) chloride paper.

D. The solid has a sharp melting point.

44. Which of the following substances has a sharp melting point?

A. Sodium sulphate crystal

B. Wax

C. Gas oil

D. Ink

45. Which of the following statements concerning the purity of a solid are correct?

(1) It can be checked by determining the melting point of the solid.

(2) It is only a relative idea.

(3) A solid is pure if the difference between the temperature at which the solid starts to

melt and the temperature at which the solid melts completely is smaller than 0.5C.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

Section 64.7

46. Which of the following methods is the most suitable for separating crude oil?

A. Chromatography

B. Simple distillation

C. Fractional distillation

D. Use of a separating funnel

47. Which of the following combinations concerning the substance and its separation

method is correct?

Separation method Application

A. Chromatographic methods Chemicals in Chinese herbal medicines

B. Solvent extraction Ethanol and water

C. Evaporation Oil and water

D. Filtration Salt and sea water


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48. Which of the following combinations concerning a separation method and its

application is correct?

Separation method Application

A. Crystallization Getting fresh water from sea water

B. Distillation Getting impure common salt from sea water

C.

Evaporation

Separating pure copper(II) sulphate from its

solution

D. Filtration Separating mud from muddy water

49. There is a mixture of propan-1-ol (b.p. = 97.2C) and propan-2-ol (b.p. = 82.4C).

Which of the following is the best method to separate propan-1-ol from the mixture?

A. Liquid-liquid extraction

B. Evaporation

C. Simple distillation


50. Which of the following is the best method to separate diethyl ether and water?

A. Use of a separating funnel

B. Evaporation

C. Simple distillation


Section 65.1

51. Which of the following ions CANNOT be determined quantitatively by gravimetric

analysis?

(1) Ag+

(2) K+

(3) NO3

A. (1) only

B. (2) only

C. (1) and (3) only

D. (2) and (3) only


14

52. What is the percentage by mass of Cu in CuSO4 • 5H2O?

A. 63.9%

B. 39.8%

C. 35.8%

D. 25.4%

53. Find the mass of water of crystallization in 6.0 g hydrated copper(II) sulphate,

CuSO4 • 5H2O.

A. 0.36 g

B. 0.43 g

C. 0.61 g

D. 2.17 g

54. Which of the following statements are INCORRECT?

(1) The mass of precipitate should be measured immediately after taking out from the

electronic oven.

(2) A desiccator can be used to dry the precipitate.

(3) An ordinary top-loading balance is used to measure weights with an accuracy of four

or five decimal places.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

55. Which of the following statements concerning suction filtration are INCORRECT?

(1) The filter paper should be wetted with distilled water.

(2) The water pump can be turned off at any moment during filtration.

(3) The pressure inside the filtering flask is increased when the water pump is turned on.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)


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56. In the gravimetric analysis of a compound, the following data were obtained.

Mass of filter paper and precipitate after filtration = 4.5261 g

Mass of filter paper before filtration = 2.5874 g

Which of the following statements are correct?

(1) The mass of precipitate formed in the experiment was 1.9387 g.

(2) Both masses were measured by an ordinary top-loading balance.

(3) The mass of precipitate formed should be found by weighing by difference.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

Section 65.2

7. Which of the following statements concerning calcium ions are correct?

(1) Its concentration indicates the hardness of water.

(2) Its concentration can be determined by precipitation with oxalic acid.

(3) It causes deposits in water pipes.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

58. Which of the following ions can form precipitate with calcium chloride?

(1) Pb2+

(2) C2O42

(3) NO3

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

59. The barium content of a sample solution was analysed. An excess of sodium sulphate

was added to 500.0 cm3 of sample solution. The mass of barium sulphate precipitated was

0.046 g. What is the concentration of barium (in g dm3) in the sample solution?

A. 0.027 g dm3

B. 0.046 g dm3

C. 0.054 g dm3

D. 0.092 g dm3


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60. Which of the following reactions can be applied for gravimetric analysis?

(1) The reaction between copper(II) sulphate solution and excess ammonia solution.

(2) The reaction between barium hydroxide solution and sodium sulphate solution.

(3) The reaction between calcium chloride solution and lead(II) nitrate solution.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

61. 2.560 g of impure copper(II) sulphate sample was dissolved in water and precipitated

with excess sodium hydroxide solution. If 1.245 g copper(II) hydroxide was obtained,

what is the percentage of copper(II) sulphate in the impure sample?

A. 39.90%

B. 48.21%

C. 79.80%

D. 96.42%

Sections 65.365.4

62. Which of the following statements concerning the apparatus routinely used for titration

is INCORRECT?

A. Pipette is used to transfer a fixed amount of a solution accurately.

B. Measuring cylinder is used to deliver variable volumes of a solution accurately. C. Electronic balance is used for fast and accurate weighing.

D. Volumetric flask is used to make up a certain solution to a specific volume

accurately.

63. Which of the following statements about Mohr’s method is INCORRECT?

A. The pH of the reaction mixture should not be too high to prevent the formation

of undesirable precipitates.

B. The pH of the reaction mixture should not be too low to prevent the conversion

of chromate ions to dichromate ions.

C. This method is used to determine the concentration of chloride ions in a water

sample.

D. A bluish-green precipitate can be observed at the end point of the titration.


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64. Which of the following are used to detect the end point of a precipitation titration?

(1) Conductivity of the reaction mixture

(2) Mass of the precipitates formed

(3) A suitable indicator

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

65. What is the molarity of a 500.0 cm3 solution containing 2.65 g of sodium carbonate?

A. 0.025 M

B. 0.050 M

C. 0.075 M

D. 1.000 M

66. Which of the following statements concerning Mohr’s method are correct?

(1) It is used to determine the chloride ion concentration of a water sample by

precipitation titration against a silver nitrate solution.

(2) The indicator used in this method is potassium dichromate.

(3) It should be carried out in pH 6.59.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

67. A 500.0 cm3 potassium chloride solution was prepared by dissolving potassium

chloride in distilled water. 25.0 cm3 of the solution was titrated with 0.300 M silver nitrate

solution. 28.90 cm3 of silver nitrate solution was required to reach the end point in the

titration. What is the number of moles of potassium chloride present in the 500.0 cm3

solution?

A. 0.009 mol

B. 0.029 mol

C. 0.173 mol

D. 8.670 mol


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68. Which of the following is the suitable pH for Mohr’s method?

A. pH < 2

B. pH = 36.5

C. pH = 6.59

D. pH 10

69. Which of the following statements are correct?

(1) A specific volume of analyte is transferred into a conical flask for titration by a

pipette.

(2) The titrant is run from the burette into the conical flask.

(3) Precipitation titration is a type of volumetric analysis.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

70. Which of the following statements concerning Mohr’s method are correct?

(1) It is a kind of precipitation titration.

(2) Potassium dichromate is used as the indicator.

(3) It should be carried out in pH 6.59.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

Section 65.5

71. Which of the following is used as an indicator for the titration between iodine and

sodium thiosulphate solution?

A. Potassium chromate

B. Methyl orange

C. Phenolphthalein

D. Starch solution


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72. Which of the following statements concerning the determination of water quality are

correct?

(1) It applies permanganate index to show the water quality.

(2) The smaller the permanganate index, the better is the quality of water.

(3) It involves redox titrations.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

73. Which of the following statements concerning permanganate index is INCORRECT?

A. Permanganate index should not exceed 4 mg dm3 according to the national

standard.

B. The determination of permanganate index involves a redox titration.

C. Excess sodium oxalate solution is added to remove any residual potassium

permanganate.

D. An indicator is required in the titration.

Section 66.1

74. Which of the following are the advantages of using instrumental analytical methods

over conventional analytical methods?

(1) Less human error is involved.

(2) Less harmful chemicals and apparatus are involved.

(3) Less sample is used.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

Section 66.2

75. Which of the following chemical solutions can be quantitatively analysed by a

colorimeter?

(1) Potassium permanganate solution

(2) Copper(II) sulphate solution

(3) Sodium chloride solution

A. (1) and (2) only

B. (1) and (3) only


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C. (2) and (3) only

D. (1), (2) and (3)

76. The following diagram shows a calibration curve of a blue food dye. If a sample

containing unknown concentration of blue dye has an absorbance of 0.56. What is the

concentration of the blue dye?

A. 6.0 g dm3

B. 6.5 g dm3

C. 7.0 g dm3

D. 7.5 g dm3

Section 66.3

77. Which of the following absorption bands must be observed in IR spectrum of propene?

A. A strong absorption peak between 16101680 cm1.

B. A strong and broad absorption band at around 3200 cm1.

C. A strong absorption peak between 22002280 cm1.

D. A strong absorption peak between 33503500 cm1.

Abs

orba

nce

Concentration of blue dye (g dm3)


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78. What is the name of compound that gives the following infrared spectrum?

A. Butanoic acid

B. Butane

C. Butan-1-ol

D. Butan-2-one

79. Which of the following information obtained from the infrared spectrum can be used

to distinguish between ethanoic acid and ethanol?

A. The presence of broad absorption peaks at 32303670 cm1.

B. The absence of broad absorption peaks at 32303670 cm1.

C. The presence of absorption peaks at 16801750 cm1.

D. The presence of absorption peaks at 27202820 cm1.

Tra

nsm

itta

nce

(%)

Wavenumber (cm1)


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A. Propene

B. Butanoic acid

C. Methyl ethanoate

D. Butan-1-ol


A. Pent-1-ene

B. Propan-2-one

C. Propanenitrile

D. Propan-1-ol

Tra

nsm

itta

nce

(%)

Wavenumber (cm1)

Tra

nsm

itta

nce

(%)

Wavenumber (cm1)


23

82. Which of the following statements concerning vibrational frequency are correct?

(1) It is unique for each type of bond.

(2) Weaker bonds vibrate at higher frequencies than stronger bonds.

(3) Lighter atoms usually vibrate at higher frequencies than heavier atoms.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

83. Which of the following statements concerning infrared spectroscopy are correct?

(1) Wavenumber is directly proportional to frequency.

(2) CN bond vibrates at a higher frequency than C=C bond.

(3) A strong and broad absorption peak at around 3300 cm1 corresponds to the

absorption of OH bond in alcohols or carboxylic acids.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

84. Which of the following absorption peaks is observed in the IR spectrum of phenol?

A. A strong peak at around 1700 cm1

B. A strong peak at around 2100 cm1

C. A strong peak at around 2250 cm1

D. A strong peak at around 3230 cm1

85. Which of the following is the correct descending order of bond strength?

A. C=C > C=O > C C > C N

B. C=C > C C > C=O > C N

C. C N > C=O > C C > C=C

D. C N > C C > C=O > C=C


24

Section 66.4

86. Which of the following statements concerning mass spectrometry is correct?

A. In the mass spectrum, the y-axis is the relative abundance of positive ions

generated while the x-axis is mass.

B. The magnetic field in the mass spectrometer is used to accelerate the ions. C. The positive ions in the mass spectrometer are generated by bombarding the

gaseous sample with fast moving electrons. D. Ions with a higher mass-to-charge ratio are deflected more than those with a

lower mass-to-charge ratio.

87. Which of the following statements concerning mass spectrometry is INCORRECT?

A. It can distinguish between a pair of structural isomers.

B. The sample analysed by the mass spectrometry must be pure.

C. The mass spectrometry has a detection limit.

D. The base peak must be the peak corresponding to the molecular ion.

88. Referring to the mass spectrum of chloromethane, what is the peak height ratio of

CH335Cl+ : CH3

37Cl+?

A. 2 : 1

B. 1 : 2

C. 1 : 3

D. 3 : 1

89. Which of the following peaks can be observed in the mass spectrum of hexane?

(1) The peak at m/e = 43



A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

90. Which of the following statements concerning the molecular ion of a compound in a

mass spectrum are correct?

(1) It gives the highest value of m/e ratio.

(2) Its relative abundance must be the highest.

(3) The m/e ratio of the molecular ion shows the relative molecular mass of the

compound.


25

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

91. Which of the following statements concerning base peak is correct?

A. It is the peak with the highest mass-to-charge ratio.

B. It must be the molecular ion peak.

C. It is the peak with the highest relative abundance.

D. It is the peak contributed by the isotope of an element of the compound.

92. The mass spectrum of pentan-3-one is shown below. Which of the following

combinations are correct?

Ion m/e ratio

(1) CH3CH2COCH2CH3+ 86

(2) CH3CH2CO+ 57

(3) CH3CH2+ 29

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

Rel

ativ

e ab

unda

nce

(%)

m/e


26

93. Which of the following statements are correct?

(1) Colorimetry determines the concentration of a coloured chemical solution by

measuring the amount of light it absorbs.

(2) Infrared spectroscopy identifies particular functional groups in molecules.

(3) Mass spectroscopy identifies the structures of unknown substances.

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

94. Which of the following analytical instruments CANNOT be used to distinguish

between a pair of enantiomers?

(1) A colorimeter

(2) An infrared spectrometer

(3) A mass spectrometer

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

95. The concentration of copper(II) sulphate solution can be determined by

(1) an infrared spectrometer.

(2) a colorimeter.

(3) a mass spectrometer.

A. (1) only

B. (2) only

C. (1) and (3) only

D. (2) and (3) only

96. Which of the following information can be obtained from the mass spectrum?

(1) The empirical formula of a compound

(2) The relative molecular mass of a compound

(3) The structure of a compound

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)


27

Section 66.5

97. Which of the following analytical methods are necessary to determine the structural

formula of an unknown organic compound?

(1) Colorimetry

(2) Infrared spectroscopy

(3) Mass spectroscopy

A. (1) and (2) only

B. (1) and (3) only

C. (2) and (3) only

D. (1), (2) and (3)

analytical chemistry mc questions

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aqueous solution

silver nitrate solution

ironii nitrate solution

excess ammonia solution

little ammonia solution

sodium iodide solution

following statements

following compounds