CE : Section 3 MC P.1Section 3 Chemical Cells and Electrolysis

93-CE1. The oxidation number of copper remains

unchanged whenA. magnesium ribbon is added to copper(II)

sulphate solution.B. sodium carbonate solution is added to

copper(II) nitrate solution.C. carbon is heated with copper(II) oxide.D. copper foil is burnt in chlorine.

2.

In the above experiment, which of the following major products will be liberated at the electrodes?

cathode anodeA. magnesium oxygenB. magnesium bromineC. hydrogen bromineD. hydrogen oxygen

3.

With reference to the above diagram, which of the following statements is correct?A. The electrode made of metal X is the positive

pole.B. Copper is at a higher position in the

electrochemical series than metal X.C. The mass of the copper electrode decreases.D. The mass of the electrode made of metal X

decreases.

4. In which of the following equations does the underlined substance undergo reduction?A. 2H2O + 2K 2KOH + H2B. Fe2(SO4)3 + 2KI 2FeSO4 + K2SO4 + I2C. 2H2S + SO2 3S + 2H2OD. NaClO + SO2 + H2O NaCl + H2SO4

94-CE5. In which of the following experiments will a redox

reaction occur?A. adding copper turnings to iron(II) nitrate

solutionB. adding bromine water to potassium chloride

solutionC. adding iron filings to silver nitrate solutionD. adding sodium chloride solution to silver

nitrate solution

6. When a substance X is electrolyzed using platinum electrodes, a gas is collected at each electrode. X may beA. silver nitrate solution.B. potassium chloride solution.C. molten sodium chloride.D. molten copper(II) chloride.

7. There is a gradual change in the properties of halogens from chlorine to iodine. Which of the following properties are in the order

chlorine < bromine < iodine?(1) oxidizing power(2) density(3) boiling point

A. (1) & (2) only B. (2) & (3) only

C. (1) & (3) only D. (1), (2) & (3)

8. In which of the following reactions does sulphur dioxide act as an oxidizing agent?A. SO2 + 2Mg 2MgO + SB. SO2 + 2KOH K2SO3 + H2OC. SO2 + Cl2 + 2H2O H2SO4 + 2HClD. 5SO2 + 2KMnO4 + 2H2O

K2SO4 + 2MnSO4 + 2H2SO4

95-CE9. Both rubidium (Rb) and sodium are elements in

Group I of the Periodic Table, but rubidium is more reactive than sodium. When a rubidium hydroxide is electrolysed using platinum electrode, hydrogen gas is liberated at the cathode.Which of the following statements is a correct explanation for the phenomenon described above?A. The H+(aq) ion accepts an electron more

readily than the Rb+(aq) ion.B. The H+(aq) ion is more mobile than the Rb+

(aq) ion and migrates faster to the cathode.C. Rubidium is first liberated, but it reacts

immediately with water to give hydrogen gas.D. The concentration of H+(aq) ions is higher

than that of Rb+(aq) ions in the rubidium hydroxide solution.

10. In which of the following equations does the underlined substance become reduced?A. CuSO4 + Zn ZnSO4 + CuB. 2FeCl2 + Cl2 2FeCl3C. Pb(OH)2 + 2HNO3 Pb(NO3)2 + 2H2OD. MgCO3 + 2HCl MgCl2 + CO2 + H2O

11. Which of the following statements concerning a silver oxide cell is/are correct?

(1) The cell is rechargeable.(2) The cell can maintain a steady voltage

during discharge.(3) The positive electrode of the cell is

silver oxide.A. (1) only B. (2) onlyC. (1) & (3) only D. (2) & (3) only

12. A student tries to electroplate an iron ring with nickel using the set-up shown below.

Which of the following combinations is correct?Solution X Anode Cathode

A. Iron(II) sulphate Iron ring Nickel rodB. Iron(II) sulphate Nickel rod Iron ringC. Nickel(II) sulphate Iron ring Nickel rodD. Nickel(II) sulphate Nickel rod Iron ring

13. Refer to the following chemical equation:

Fe2O3(s) + 3CO(g) 2Fe(s) + 3CO2(g)

Which of the following statements is/are correct?(1) Carbon monoxide is an oxidizing agent.(2) The oxidation number of carbon

changes from +2 to +4.(3) The oxidation number of iron changes

from +2 to 0.A. (1) only B. (2) onlyC. (1) & (3) only D. (2) & (3) only

CE : Section 3 MC P.214. Astatine is a Group VII element below iodine in the

Periodic Table. Which of the following statements concerning astatine is/are correct?

(1) It is a liquid at room temperature and pressure.

(2) It reacts with sodium to form an ionic compound.

(3) It is a stronger oxidizing agent than iodine.

A. (1) only B. (2) onlyC. (1) & (2) only D. (2) & (3) only

15. In the set-up shown below metal X is more reactive than metal Y.

Which of the following statements concerning this set-up is/are correct?

(1) Electrolysis occurs inside the lemon.(2) Chemical energy is changed into

electrical energy.(3) Electrons flow from metal Y to metal X

in the external circuit.A. (1) only B. (2) onlyC. (1) & (3) only D. (2) & (3) only

96-CE16.

Which of the following metals would produce the smallest voltage in the above set-up?A. iron B. aluminiumC. copper D. magnesium

17. step 1 step 2 step 3 step 4 N2 NH3 NO NO2 HNO3

Which step in the above flow chart involves the largest change in oxidation number of nitrogen?A. step 1 B. step 2C. step 3 D. step 4

18. Which of the following substances are commonly found in the waste water produced by electroplating factories?

(1) acids(2) alkalis(3) cyanides

A. (1) & (2) only B. (1) & (3) onlyC. (2) & (3) only D. (1), (2) & (3)

19.

Which of the following statements concerning the above set-up is correct?A. Electrons flow from the lead electrode to the

magnesium electrode through the external circuit.

B. Electrons flow through the salt bridge.C. The mass of the lead electrode remains

unchanged.D. Oxidation occurs at the magnesium

electrode.

Q.20 & Q.21 refer to the following experiment.

20. Which of the following combinations is correct?Gas X Gas Y

A. chlorine hydrogenB. chlorine oxygenC. hydrogen chlorineD. oxygen hydrogen

21. Which of the following statements concerning the above experiment is/are correct?

(1) Platinum electrodes should be used.(2) The concentration of Na+(aq) ions

around the cathode increases.(3) The solution changes from colourless to

pink.A. (1) only B. (2) onlyC. (1) & (3) only D. (2) & (3) only

CE-9722. Which of the following statements concerning the

elements in the third period of the Periodic Table is correct?A. Both sulphur and chlorine can be reduced by

aqueous sodium sulphite.B. Magnesium is a stronger reducing agent than

sodium.C. Phosphorus and chlorine form a covalent

compound.D. Magnesium burns in oxygen to form an acidic

compound.

23. During the electrolysis of 1M copper(II) chloride solution using copper electrodes, which of the following changes would occur at the electrodes?

Cathode AnodeA. hydrogen liberated chlorine liberatedB. copper deposited chlorine liberatedC. copper dissolved copper depositedD. copper liberated copper dissolved

24. Which of the following conversions involves the smallest change in oxidation number of the underlined element?

CE : Section 3 MC P.3A. C(s) CO2(g)B. NO3

-(aq) NO2(g)C. SO3

2-(aq) SO42-(aq)

D. MnO4-(aq) Mn2+(aq)

25. Which of the following combinations in INCORRECT?

Chemical Method of storageA. calcium under waterB. potassium under paraffin oilC. ethanol in a cool placeD. potassium permanganate in a brown bottle

Solution

26.

A zinc-carbon cell is connected to a voltmeter as shown in the above diagram. Which of the following statements concerning the set-up is INCORRECT?A. Electrons flow from the zinc case to the

carbon rod in the external circuit.B. The zinc case gradually becomes thinner as

the cell discharges.C. Manganese(IV) oxide acts as an oxidizing

agent.D. Ammonium chloride acts as a reducing agent.

CE-98Directions: Question 27 and 28 refer to the following experiment:The circuit shown below is set-up and the solid lead(II) bromide is heated until it becomes molten.

27. Which of the following statements concerning the experiment is INCORRECT?A. The bulb lights up.B. A reddish brown gas is liberated at electrode

X.C. Electrodes X and Y can be made of nichrome.D. Oxidation occurs at electrode Y.

28. Which of the following can be deduced from the experimental results?A. Solid lead(II) bromide contains mobile ions.B. Molten lead(II) bromide contains delocalized

electrons.C. Molten lead(II) bromide can be decomposed

by electricity.

D. Solid lead(II) bromide is a covalent compound but molten lead(II) bromide is an ionic compound.

29. A part of the Periodic Table is shown below.Group

I II III IV V VI VII O1 a

Period 2 b c d3 e

Which of the following statements is correct?A. The outermost electron shell of an atom of a

is an octet structure.B. The metallic character of the Period 2

elements increases from b to d.C. c forms an ionic compound with d.D. e is a strong oxidizing agent.

30. Consider the following experiment.

Which of the following statements concerning the above experiment is correct?A. Permanganate ions migrate into the salt

bridge.B. Electrons flow from electrode X to electrode Y

in the external circuit.C. Carbon electrodes are used because they are

chemically inert.D. The half equation for the change occurring at

electrode Y is Fe2+ + 2e- Fe.

31. In which of the following reactions does the underlined substance act as a reducing agent?A. SO2 + 2H2S 3S + 2H2OB. Pb(NO3)2 + H2SO4 PbSO4 + 2HNO3C. 2HCl + MgO MgCl2 + H2OD. 2KBr + Cl2 2KCl + Br2

99-CE32. In which of the following reactions is the

underlined reactant reduced?A. Cu 2+ + 2OH- Cu(OH)2B. SO2 + 2Mg 2MgO + SC. 2NH3 + 3CuO 3Cu + N2 + 3H2OD. Zn + 2AgNO3 Zn(NO3)2 + 2Ag

33. Which of the following statements concerning bromine and chlorine is INCORRECT?A. They exist as diatomic molecules.B. Their atoms have the same number of

outermost shell electrons.C. They form ions with a single negative charge.D. Bromine is a stronger oxidizing agent than

chlorine.

34. Consider the electrolysis experiment shown below:

Which of the following statements concerning this experiment is correct?A. The mass of the impure copper rod

decreases.B. The blue colour of the copper(II) sulphate

solution gradually fades off.C. Oxidation takes place at the pure copper rod.

CE : Section 3 MC P.4D. The electrolysis process can enhance the

corrosion resistance of copper.

35. Potassium permanganate solution acidified with dilute sulphuric acid is a commonly-used oxidizing agent. Dilute nitric acid is not used to acidify potassium permanganate solution becauseA. nitric acid is more expensive than sulphuric

acid.B. dilute nitric acid is an oxidizing agent and

would react with the reducing agent.C. nitric acid decomposes more readily than

sulphuric acidD. dilute nitric acid would react with potassium

permanganate solution

36. In an experiment, sulphur dioxide is passed into an iodine solution which is prepared by dissolving some iodine in potassium iodide solution. Which of the following statements concerning this experiment is correct?A. The colour of the iodine solution changes

from purple to colourless.B. A brown solid is formed.C. A displacement reaction occurs.D. Sulphur dioxide is oxidized to sulphate ions.

37. Consider the following chemical cell:

Which of the following changes would lead to an increase in the voltage of the cell?

(1) The zinc electrode is replaced with a magnesium electrode.

(2) The copper electrode is replaced with an iron electrode.

(3) The sodium chloride solution is replaced with a sugar solution.

A. (1) only B. (2) onlyC. (1) & (3) only D. (2) & (3) only

38. Consider the following experiment:

Which of the following statements concerning the experiment are correct?

(1) Gas bubbles are evolved at electrode X.(2) An orange colour gradually appears in

the solution around electrode Y.(3) The experiment can be used to show

that ions migrate towards oppositely charged electrodes.

A. (1) & (2) only B. (1) & (3) onlyC. (2) & (3) only D. (1), (2) & (3)

00-CE39. Caesium (Cs) is a Group I element in the Periodic

Table and its relative atomic mass is greater than that of potassium. Which of the following statements concerning caesium is INCORRECT?A. Caesium is a weaker reducing agent than

potassium.B. Caesium reacts violently with water.C. Caesium is a soft metal.D. Caesium reacts with oxygen to form an oxide

with formula Cs2O.

40. Which of the following gases are the major products liberated in the electrolysis of

concentrated sodium chloride solution using carbon electrodes?

Cathode AnodeA. hydrogen chlorineB. chlorine hydrogenC. hydrogen oxygenD. oxygen hydrogen

41. Consider the following equation: 3Zn(s) + 2NO3

-(aq) + 8H+(aq) 3Zn2+(x) + 2NO(y) + 4H2O(z)

Which of the following combinations is correct?x y z

A. aq g aqB. aq g lC. aq aq lD. l g aq

42. Which of the following is NOT a redox reaction?A. Fe2(SO4)3 + H2S 2FeSO4 + S + H2SO4B. 2Al + 6HCl 2AlCl3 + 3H2C. CaCO3 + CO2 + H2O Ca(HCO3)2D. 2KClO3 2KCl + 3O2

43. In which of the following substances does nitrogen have the smallest oxidation number?A. NH3 B. NOC. N2O D. N2

44. Consider the chemical cell shown below:

Which of the following statements concerning the cell is/are correct?

(1) Oxidation takes place at the copper electrode.

(2) The concentration of magnesium ions in beaker X increases.

(3) The salt bridge allows electrons to flow from one electrode to the other electrode.

A. (1) only B. (2) onlyC. (1) & (3) only D. (2) & (3) only

45. Which of the following statements concerning a zinc-carbon cell are correct?

(1) The ammonium chloride in the cell acts as an electrolyte

(2) The manganese(IV) oxide in the cell acts as an oxidizing agent.

(3) The zinc case of the cell acts as the positive terminal.

A. (1) & (2) only B. (1) & (3) onlyC. (2) & (3) only D. (1), (2) & (3)

01-CE46. Which of the following statements concerning the

formation of chloride ions from chlorine atoms is correct?A. The number of shells occupied by electrons

in a chlorine atom equals that in a chloride ion.

B. The atomic number of chlorine increases by 1.

C. The mass number of chlorine increases by 1.

D. The change is an oxidation.

47. Consider the half equations of a redox reaction:8H+(aq) + MnO4

-(aq) + 5e- Mn2+(aq) + 4H2O(l) C2O4

2-(aq) 2CO2(g) + 2e-

How many moles of MnO4-(aq) ions will react

completely with one mole of C2O42-(aq) ions?

A. 0.4 B. 1.0C. 2.5 D. 5.0

CE : Section 3 MC P.5

48. Which of the following equations represents a redox reaction?A. NH4

+(aq) + OH-(aq) NH3(g) + H2O(l)B. 2CrO4

2-(aq) + 2H+(aq) Cr2O72-(aq) + H2O(l)

C. 2FeSO4(s) Fe2O3(s) + SO3(g) + SO2(g)D. 2NaHCO3(s) Na2CO3(s) + H2O(l) + CO2(g)

49. Consider the half equation:IO3

-(aq) + xH2O(l) + ye- I-(aq) + zOH-(aq)Which of the following combinations is correct?

x y zA. 1 2 2B. 2 4 4C. 3 6 6D. 4 8 8

50. The oxidation number of lead in [Pb(OH)4]2- isA. -2 B. +2C. +4 D. +6

51. Consider the set-up shown below:

Which of the following statements are correct?(1) The solution around electrode X turns

brown.(2) The mass of electrode X remains

unchanged(3) Reduction occurs at electrode Y.

A. (1) & (2) only B. (1) & (3) onlyC. (2) & (3) only D. (1), (2) & (3)

02-CE52. Compound X dissolves in water to give a

colourless solution. When chlorine gas is bubbled into the solution, the solution turns brown. X is probablyA. ammonium iodide B. iron(II) sulphateC. sodium sulphite D. potassium hydroxide

53. Sodium chromate, Na2CrO4, dissolves in water to give a yellow solution. When dilute hydrochloric acid is added to the solution, the following reaction occurs:

2CrO42-(aq) + 2H+(aq) Cr2O7

2-(aq) + H2O(l)Which of the following statements concerning the reaction is correct?A. The colour of the solution changes from

yellow to green.B. Chromate ions act as a reducing agent.C. The oxidation number of oxygen remains

unchanged during the reaction.D. The reaction is a neutralization.

54. Consider the set-up shown below:

Electrons flow from X to Y in the external circuit. Which of the following combinations in correct?

X Y ZA. carbon silver silver nitrate solution

B. zinc magnesium magnesium sulphate solutionC. carbon carbon copper(II) sulphate solutionD. zinc carbon silver nitrate solution

55. Which of the following equations represents a redox reaction?A. Ca(HCO3)2 + 2HCl CaCl2 + 2CO2 + 2H2OB. PCl3 + Cl2 PCl5C. Fe3+ + 3OH- Fe(OH)3D. Al2O3 + 2NaOH 2NaAlO2 + H2O

56. The symbol of vanadium is V. What is the oxidation number of vanadium in NH4VO3?A. -1 B. +3C. +5 D. +6

57. Which of the following statements concerning Group VII elements and their ions are correct?(1) Chlorine has the highest oxidizing power

among chlorine, bromine and iodine.(2) Iodide ions have the highest reducing power

among chloride, bromide ion and iodide ions.(3) Bromine is a volatile liquid at room

temperature and pressure.A. (1) & (2) only B. (1) & (3) onlyC. (2) & (3) only D. (1), (2) & (3)

Direction : Each question below consists of two statements. Decide whether each of the two statements is true or false; if both are true, then decide whether or not the second statement is a correct explanation of the first statement. Then select one option from a to D according to the following table:

A. Both statements are true and the 2nd statement is a correct explanation of the 1st statement.B. Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement.C. Only one statement is true while the other is false.D. Both statements are false.

1st statement 2nd statement

58. Potassium iodide solution turns brown on adding chlorine water.

The iodide ions are reduced by chlorine to give iodine.

59. The yellow colour of bromine water disappears when it is mixed with sodium sulphite solution.

The bromine water is reduced to bromide ions by the sulphite ions.

60. Both molten lead(II) bromide and iron can conduct electricity.

They are both electrolytes.

61. During electrolysis, reduction occurs at the cathode.

Cations gain electrons at the cathode.

62. Magnesium is a stronger oxidizing agent than sodium.

Mg2+(aq) accepts electrons more readily than Na+(aq).

63. Zinc-carbon dry cells are rechargeable. The electrolyte used in zinc-carbon dry cells in potassium hydroxide.

64. The resistance of aluminium to corrosion can be enhanced by anodization.

During anodization, aluminium oxide on the metal surface is reduced to aluminium.

65. Bromine water can be used to distinguish between sodium sulphate solution and sodium sulphite solution.

Bromine can be reduced by sodium sulphite to colourless bromide ions, but not by sodium sulphate.

66. During electrolysis, oxidation takes place at the cathode.

Cations accept electrons and are discharged at the cathode.

Section 31 2 3 4 5 6 7 8 9 10

0+ B C D C C B B A A A10+ D D B B B C B D D A20+ D C D B A D B C D C30+ D B D A B D A D A A40+ B C A B A A A C C B50+ D A C D B C D C A C60+ A C D C A C