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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
Sulphuric acid and Sulphur dioxide
Public Exam Questions :
1. Concentrated sulphuric acid turns blue litmus paper red and then black. On the basis of these
colour changes, which of the following deductions concerning concentrated sulphuric acid are
correct?
(1) It contains H+(aq) ions.
(2) It is an oxidizing agent.
(3) It is a dehydrating agent.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
(HKCEE 1994)
2. 1st statement : At room temperature and pressure, the molar volume of oxygen gas is greater
than that of hydrogen gas.
2nd statement : The relative atomic mass of oxygen is greater than that of hydrogen.
(HKCEE 1994)
3. The reaction of cane sugar and concentrated sulphuric acid may be represented by the following
equation.
In this reaction, concentrated sulphuric acid acts as
A. a strong acid.
B. an oxidizing agent.
C. a drying agent.
D. a dehydrating agent.
(HKCEE 1995)
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
4. Refer to the following chemical equation :
Fe2O3(s) + 3CO(g) 2Fe(s) + 3CO2(g)
What volume of carbon dioxide, measured at room temperature and pressure, is produced if
224g of iron are formed?
(relative atomic mass : Fe = 56;
Molar volume of gas at room temperature and pressure = 24 dm3)
A. 16 dm3
B. 36 dm3
C. 72 dm3
D. 144 dm3
(HKCEE 1995)
5. Which of the following statements concerning the Contact Process is/are correct?
(1) The sulphur dioxide used in the process can be produced by roasting sulphide ores.
(2) A gaseous mixture of sulphur dioxide and oxygen in the mole ratio of 1 : 2 is passed
into the catalytic conversion chamber.
(3) The sulphur trioxide produced is absorbed by water in the absorption tower.
A. (1) only
B. (2) only
C. (1) and (3) only
D. (2) and (3) only
(HKCEE 1995)
6. Which of the following experiments can be used to show that concentrated sulphuric acid is a
dehydrating agent?
A. adding it to copper(II) oxide powder
B. adding it to copper(II) sulphate crystals
C. adding it to calcium carbonate powder
D. adding it to sodium chloride crystals
(HKCEE 1996)
7. In an experiment, 1.6g of sulphur are burnt completely in air to form sulphur dioxide. What
volume of sulphur dioxide, measured at room temperature and pressure, is formed?
(Relative atomic mass : S = 32.0;
Molar volume of gas at room temperature and pressure = 24.0 dm3)
A. 0.6 dm3
B. 1.2 dm3
C. 2.4 dm3
D. 12.0 dm3
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
(HKCEE 1996)
8. One mole of each of the following compounds is burnt completely in oxygen. Which compound
requires the greatest volume of oxygen, measured at room temperature and pressure, for
complete combustion?
A. carbon monoxide
B. ethane
C. ethene
D. ethanol
(HKCEE 1996)
9. Under certain conditions, 60cm3 of a gaseous compound, NxOy, decompose completely to give
60cm3 of nitrogen gas and 30cm3 of oxygen gas. (All gas volumes are measured at the same
temperature and pressure.)
Which of the following combinations is correct?
x y
A. 1 1
B. 1 2
C. 2 1
D. 2 3
(HKCEE 1996)
10. Which of the following statements concerning one mole of nitrogen gas is/are correct?
(1) It has a mass of 14.0g.
(2) It occupies the same volume as 4.0g of helium gas at room temperature and pressure.
(3) It contains 6.02 1023 atoms of nitrogen.
(Relative atomic masses : He = 4.0; N = 14.0;
Avogadro constant = 6.02 1023 mol-1)
A. (1) only
B. (2) only
C. (1) and (3) only
D. (2) and (3) only
(HKCEE 1996)
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
11. In which of the following reactions does sulphur dioxide act as a reducing agent?
(1) the production of sulphuric acid in the Contact Process
(2) the bleaching of a red petal
(3) the decolourization of bromine water
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
(HKCEE 1996)
12. The atomic number of element X is 16. Which of the following statements concerning X are
correct?
(1) X can react with calcium to form an ionic compound.
(2) The oxide of X dissolves in water to form an acidic solution.
(3) X can conduct electricity in its molten state.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
(HKCEE 1996)
13. 1st statement : The volume of hydrogen liberated at room temperature and pressure by the
reaction between 10cm3 of 10M hydrochloric acid and excess zinc granules is
greater than that between 50cm3 of 2M hydrochloric acid and excess zinc
granules.
2nd statement : 10M hydrochloric acid is a stronger acid than 2M hydrochloric acid.
(HKCEE 1996)
14. Which of the following gases occupies the largest volume at room temperature and pressure?
(Relative atomic masses : H = 1.0; C = 12.0; N = 14.0; O = 16.0;
Molar volume of gas at room temperature and pressure = 24.0 dm3)
A. 1.0g of ammonia
B. 2.0g of nitrogen
C. 3.0g of oxygen
D. 4.0g of carbon dioxide
(HKCEE 1997)
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
15. An iron nail is heated with concentrated sulphuric acid. Which of the following combinations is
correct?
Gas given off Colour of solution formed
A. hydrogen pale green
B. hydrogen yellow
C. sulphur dioxide pale green
D. sulphur dioxide yellow
(HKCEE 1997)
16. One mole of sulphur atoms has a mass twice that of one mole of oxygen atoms. Which of the
following statements is/are correct?
(1) 2g of sulphur and 1g of oxygen each occupy the same volume at room temperature
and pressure.
(2) 2g of sulphur and 1g of oxygen each contain the same number of atoms.
(3) The number of atoms contained in one mole of sulphur is twice that contained in one
mole of oxygen.
A. (1) only
B. (2) only
C. (1) and (3) only
D. (2) and (3) only
(HKCEE 1997)
17. Concentrated sulphuric acid is corrosive to skin because
(1) it is a dehydrating agent.
(2) it is an oxidizing agent.
(3) each molecule of sulphuric acid has two ionizable hydrogen atoms.
Which of the above statements are correct?
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
(HKCEE 1997)
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
18. 7.5g of calcium carbonate is added to 50.0cm3 of 2M hydrochloric acid. What is the volume of
carbon dioxide liberated at room temperature and pressure?
(Relative atomic masses : C= 12.0; O = 16.0; Ca = 40.0;
Molar volume of gas at room temperature and pressure = 24.0 dm3)
A. 0.9 dm3
B. 1.2 dm3
C. 1.8 dm3
D. 2.4 dm3
(HKCEE 1998)
19. Which of the following experiments would produce sulphur dioxide?
(1) heating iron pyrites in air
(2) heating a mixture of iron and dilute sulphuric acid
(3) heating a mixture of copper and concentrated sulphuric acid
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
(HKCEE 1998)
20. 1st statement : One mole of water occupies the same volume as one mole of carbon dioxide at
room temperature and pressure.
2nd statement : One mole of water contains the same number of atoms as one mole of carbon
dioxide.
(HKCEE 1998)
21. Substance X gives identical product(s) when treated with dilute sulphuric acid or concentrated
sulphuric acid. X may be
A. zinc.
B. cane sugar.
C. ammonia.
D. hydrated copper(II) sulphate crystals.
(HKCEE 1999)
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
22. 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 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.
(HKCEE 1999)
23. In an experiment, 21.8g of zinc was treated with 250.0cm3 of 2.0M hydrochloric acid. What
volume of hydrogen was liberated at room temperature and pressure?
(Relative atomic mass : Zn = 65.4;
Molar volume of gas at room temperature and pressure = 24.0 dm3)
A. 4.0 dm3
B. 6.0 dm3
C. 8.0 dm3
D. 12.0 dm3
(HKCEE 2000)
24. Which of the following statements concerning sulphur dioxide are correct?
(1) It can be prepared by heating copper turnings with concentrated sulphuric acid.
(2) It is denser than air.
(3) It can be absorbed by sodium hydroxide solution.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
(HKCEE 2000)
25. 1st statement : Concentrated sulphuric acid can turn a piece of filter paper black.
2nd statement : Concentrated sulphuric acid is a strong oxidizing agent.
(HKCEE 2000)
26. 1st statement : The volume of 10.0g of gaseous carbon dioxide is the same as the volume of
10.0g of solid carbon dioxide.
2nd statement : 10.0g of gaseous carbon dioxide contains the same number of molecules as 10.0g
of solid carbon dioxide.
(HKCEE 2000)
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
27. Consider the reaction :
4H2(g) + Fe3O4(s) 3Fe(s) + 4H2O(l)
What mass of iron would be obtained if 96.0 cm3 of hydrogen, measured at room temperature
and pressure, is consumed in the reaction?
(Relative atomic mass : Fe = 56.0;
Molar volume of gas at room temperature and pressure = 4.0 dm3)
A. 0.056 kg
B. 0.084 kg
C. 0.168 kg
D. 0.224 kg
(HKCEE 2001)
28. Suppose that the Avogadro number is L. How many atoms does 600 cm3 of oxygen at room
temperature and pressure contain?
(Molar volume of gas at room temperature and pressure = 24.0 dm3)
A.
B.
C. 25L
D. 50L
(HKCEE 2001)
29. Consider the information below about the reaction of hydrogen with chlorine :
H2(g) + Cl2(g) 2HCl(g) H < 0
Which of the following statements can be deduced from the above information?
(1) Heat is liberated when hydrogen chloride is formed.
(2) Hydrogen and chlorine react at room temperature.
(3) When measured at room temperature and pressure, the total gas volume before the
reaction equals that after the reaction.
A. (1) only
B. (2) only
C. (1) and (3) only
D. (2) and (3) only
(HKCEE 2001)
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
30. Which of the following are correct descriptions of the uses of sulphuric acid?
(1) treatment of metal surfaces in the electroplating industry
(2) manufacture of paint additives
(3) manufacture of fertilizers
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
(HKCEE 2001)
31. 1st statement : Bromine water can be used to distinguish between sodium sulphate solution and
sodium sulphite solution.
2nd statement : Bromine can be reduced by sodium sulphite to colourless bromide ions, but not
by sodium sulphate.
(HKCEE 2001)
32. Gases X and Y react to give a gaseous product Z. The reaction can be represented by the
equation :
X(g) + 3Y(g) 2Z(g)
In an experiment, 40 cm3 of X and 60 cm3 of Y are mixed and are allowed to react in a closed
vessel. What is the volume of the resultant gaseous mixture?
(All volumes are measured at room temperature and pressure.)
A. 40 cm3
B. 60 cm3
C. 80 cm3
D. 100 cm3
(HKCEE 2002)
33. Which of the following gases contains the greatest number of molecules at room temperature
and pressure?
(Relative atomic masses : H = 1.0; N = 14.0; O = 16.0; Cl = 35.5)
A. 2.0g of hydrogen
B. 16.0g of oxygen
C. 18.0g of ammonia
D. 60.0g of chlorine
(HKCEE 2002)
- 9 -
PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
34. Starch, a natural polymer, is a carbohydrate. When concentrated sulphuric acid is added
dropwise to some starch, a black substance is formed. The reaction involved is
A. dehydration.
B. depolymerization.
C. redox reaction.
D. neutralization.
(HKCEE 2002)
35. A part of the flow diagram for the Contact Process is shown below :
Which of the following combinations is correct?
X Y Z
A. air water concentrated sulphuric acid
B. air concentrated sulphric acid oleum
C. oxygen sulphur trioxide concentrated sulphuric acid
D. oxygen water oleum
(HKCEE 2002)
36. When sulphur dioxide is bubbled into water, a colourless solution is formed. Which of the
following statements concerning the solution are correct?
(1) The solution conducts electricity better than water.
(2) The solution can change iron(III) sulphate solution from yellow to green.
(3) The solution can change potassium bromide solution from colourless to brown.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
(HKCEE 2002)
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
37. Which of the following set-ups can be used to dry moist sulphur dioxide gas?
(1) (2)
(3)
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
(HKCEE 2002)
38. Sodium azide, NaN3, is used in air bags in cars. When there is a serious collisions, the azide will
decompose to give nitrogen. The decomposition can be represented by the equation :
2NaN3(s) 2Na(s) + 3N2(g)
What is the mass of sodium azide required to produce 72 dm3 of nitrogen at room temperature
and pressure?
(Relative atomic masses : N =14.0; Na = 23.0;
Molar volume of gas at room temperature and pressure = 24.0 dm3)
A. 65.0g
B. 130.0g
C. 195.0g
D. 292.5g
(HKCEE 2003)
39. Which of the following substances will NOT react with bromine water?
A. propene
B. sulphur dioxide
C. potassium iodide solution
D. ammonium chloride solution
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
(HKCEE 2003)
40. A sample of zinc granules of mass 1.8g was added to 100cm3 of 0.25M hydrochloric acid. What
is the theoretical volume of hydrogen produced at room temperature and pressure?
(Relative atomic mass : Zn = 65.4;
Molar mass of gas at room temperature and pressure = 24.0 dm3)
A. 0.30 dm3
B. 0.33 dm3
C. 0.60 dm3
D. 0.66 dm3
(HKCEE 2003)
41. Which of the following solutions would NOT undergo a colour change when mixed with
sodium sulphite solution?
A. iodine solution
B. acidified potassium permanganate solution
C. chromium(III) sulphate solution
D. iron(III) sulphate solution
(HKCEE 2003)
42. X is a bleaching agent. X bleaches a dye by oxidation and becomes Y at the end of the
reaction. Which of the following combinations is correct?
X Y
A. Cl2(aq) Cl-(aq)
B. Cl2(aq) OCl-(aq)
C. SO2(aq) SO32-(aq)
D. SO2(aq) SO42-(aq)
(HKCEE 2003)
43. Which of the following statements concerning sulphur is/are correct?
(1) It is yellow in colour.
(2) It dissolves in water to give an acidic solution.
(3) It is used as a raw material in the Contact Process.
A. (1) only
B. (2) only
C. (1) and (3) only
D. (2) and (3) only
(HKCEE 2003)
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
44. Iron pyrite (FeS2) looks like gold and its common name is “fool’s fold”. Which of the following
methods can be used to distinguish iron pyrite from gold?
(1) comparing their densities
(2) comparing their electrical conductivity
(3) comparing the effect of heat on them
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
(HKCEE 2003)
45. A gaseous mixture consists of methane and ethane in a mole ratio of 1:1. It has a volume of
200cm3 at room temperature and pressure. What is the volume of oxygen required, measured at
room temperature and pressure, for the complete combustion of the mixture?
A. 400 cm3
B. 550 cm3
C. 700 cm3
D. 1100 cm3
(HKCEE 2004)
46. Which of the following substances, when dissolved in water, gives a solution with pH greater
than 7?
(1) chlorine
(2) calcium oxide
(3) sulphur dioxide
A. (1) only
B. (2) only
C. (1) and (3) only
D. (2) and (3) only
(HKCEE 2004)
47. 1st statement : In the Contact process, oleum instead of water is used to absorb the sulphur
trioxide produced.
2nd statement : The reaction of sulphur trioxide with water is highly exothermic.
(HKCEE 2004)
48. 1st statement : Sulphur dioxide is used to preserve dried fruits.
2nd statement : Sulphur dioxide is toxic to micro-organisms.
(HKCEE 2004)
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
Directions : Question 49 refers to the following flow scheme for the production of sulphuric acid.
49. Which of the following statements concerning the flow scheme is INCORRECT?
A. ZnS is roasted in air in Stage 1.
B. Air is used as a reactant in Stage 2.
C. Water is used to react with SO3 in Stage 3.
D. Heat energy is liberated in Stage 4.
(HKCEE 2005)
50. Which of the following combinations correctly describes the difference between sulphur dioxide
bleach and chlorine bleach?
sulphur dioxide bleach chlorine bleach
A. bleaching by oxidation bleaching by reduction
B. faster bleaching action slower bleaching action
C. temporary bleaching effect permanent bleaching effect
D. suitable for bleaching cotton suitable for bleaching silk
(HKCEE 2005)
51. NaHCO3 decomposes upon heating to form Na2CO3, CO2 and H2O. What is the volume of CO2
formed at room temperature and pressure if 336g of NaHCO3 undergoes complete
decomposition?
A. 12 dm3
B. 24 dm3
C. 48 dm3
D. 96 dm3
(HKCEE 2005)
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
Suggested Answers :
1. B 2. C 3. D 4. D 5. A 6. B 7. B 8. B 9. C 10. B
11. D 12. A 13. D 14. C 15. D 16. B 17. A 18. B 19. B 20. C
21. C 22. D 23. B 24. D 25. B 26. C 27. C 28. B 29. C 30. D
31. A 32. B 33. C 34. A 35. B 36. A 37. B 38. B 39. D 40. A
41. C 42. A 43. C 44. D 45. B 46. B 47. C 48. A 49. C 50. C
51. C 52.
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
Explanation of M.C. Questions :
1. statement (1) : correct. The presence of H+ means it has acidic properties, turning blue litmus
to red.
statement (2) : wrong.
statement (3) : correct. It will dehydrate the paper and to form carbon which is responsible for
the black color.
Ans. : B
2. 1st statement : false. According to Avogadro’s law, all gases under same conditions have same
molar volume.
2nd statement : true. Relative atomic mass of O is 16; while that of H is only 1.
Ans. : C
3. Ans. : D
4. The chemical equation is :
Fe2O3(s) + 3CO(g) 2Fe(s) + 3CO2(g)
no. of moles of Fe = = 4 mol
no. of moles of CO2 = = 6 mol
volume of CO2 = 6 24 = 144 dm3
Ans. : D
5. statement (1) : correct. Examples of sulphide ores are zinc blend and iron pyrite. They burn in
air to give SO2.
statement (2) : wrong. The equation for the reaction between SO2 and O2 is as follows :
2SO2(g) + O2(g) 2SO3(g)
The mole ratio between SO2 and O2 should be 2 : 1.
statement (3) : wrong. The absorption of SO3 by water is highly exothermic, thus instead of
using water, conc. H2SO4 is used to absorb SO3.
Ans. : A
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
6. experiment A : can’t. conc. H2SO4 behaves as an acid to react with CuO to give CuSO4 and
H2O.
H2SO4(l) + CuO(s) CuSO4(s) + H2O(l)
experiment B : can.
CuSO4nH2O(s) CuSO4(s) + nH2O(l)
experiment C : can’t. H2SO4 behaves as an acid to react with CaCO3 to give CaSO4, H2O and
CO2.
H2SO4(l) + CaCO3(s) CaSO4(s) + CO2(g) + H2O(l)
experiment D : can’t. conc. H2SO4 reacts with NaCl(s) to give HCl(g).
2NaCl(s) + H2SO4(l) Na2SO4(s) + 2HCl(g)
Ans. : B
7. the chemical equation involved :
S(s) + O2(g) SO2(g)
no. of moles of S = = 0.05 mol = no. of moles of SO2
volume of SO2 = 0.05 24.0 = 1.2 dm3
Ans. : B
8. mole ratio = volume ratio
the larger the no. of mole, the greater the volume of a gas.
substance A : 2CO(g) + O2(g) 2CO2(g)
no. of moles of O2 required = 2 mol
substance B : 2C2H6(g) + 7O2(g) 4CO2(g) + 6H2O(l)
no. of moles of O2 required = = 3.5 mol
substance C : C2H4(g) + 3O2(g) 2CO2(g) + 2H2O(l)
no. of moles of O2 required = 3 mol
substance D : C2H5OH(l) + 3O2(g) 2CO2(g) + 3H2O(l)
no. of moles of O2 required = 3 mol
Ans. : B
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
9. the chemical equation involved :
2NxOy xN2(g) + yO2(g)
x = 2
y = 1
Ans. : C
10. statement (1) : wrong. The mass should be 28.0g
statement (2) : correct.
no. of moles of He = = 1.0 mol
as they are both gases, under same conditions, they have same volume for same
no. of moles.
statement (3) : wrong.
no. of moles of N atoms = 2.0 mol
no. of N atoms = 2.0 6.02 1023 = 1.204 1024 mol
Ans. : B
11. reaction (1) : SO2(g) + O2(g) SO3(g)
SO3(g) + H2SO4(l) H2S2O7(l)
H2S2O7(l) + H2O(l) 2H2SO4(l)
The O.N. of S increases from +4 (in SO2) to +6 (in H2SO4).
reaction (2) : SO2(g) + H2O(l) + dye SO42-(aq) + 2H+(aq) + (dye-O)
The O.N. increases from +4 in (SO2) to +6 (in SO42-).
reaction (3) : SO2(g) + Br2(aq) + 2H2O(l) SO42-(aq) + 2Br-(aq) + 4H+(aq)
The O.N. increases from +4 in (SO2) to +6 (in SO42-).
Ans. : D
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
12. Element X is sulphur.
statement (1) : correct. Calcium, a metal reacts with sulphur, a non-metal to give calcium
sulphide which is an ionic compound.
Ca(s) + S(s) CaS(s)
statement (2) : correct. This oxide is called sulphur dioxide, when dissolved in water,
sulphurous acid is formed.
SO2(g) + H2O(l) H2SO3(aq)
H2SO3(aq) 2H+(aq) + SO32-(aq)
statement (3) : wrong. Even in molten state, X doesn’t contain either mobile ions or
delocalized electrons.
Ans. : A
13. 1st statement : false.
The chemical equation involved :
Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g)
Zn is in excess and HCl is limiting in both experiments.
no. of moles of H2 liberated volume of H2 liberated
In the 1st experiment, no. of moles of H2 = no. of moles of HCl
= = 0.05 mol
In the 2nd experiment, no. of moles of H2 = = 0.05 mol
In both experiments, no. of moles of H2 liberated are the same, i.e. same volume
is obtained.
2nd statement : false.
For 2M HCl and 10M HCl, they are both strong acids.
Ans. : D
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
14. volume of gas no. of moles of gas
A : no. of moles of NH3 = = 0.0588 mol
B : no. of moles of N2 = = 0.0714 mol
C : no. of moles of O2 = = 0.09375 mol
D : no. of moles of CO2 = = 0.0909 mol
Ans. : C
15. Concentrated H2SO4 acts as an oxidizing agent.
the chemical equation involved :
2Fe(s) + 6H2SO4(l) Fe2(SO4)3(aq) + 3SO2(g) + 6H2O(l)
(yellow)
Ans. : D
16. statement (1) : wrong. Sulphur is not a gas at r.t.p., it is a solid. It doesn’t occupy volume in
the air.
statement (2) : correct. No. of moles no. of particles.
no. of moles of S = = 0.0625 mol
no. of moles of O atoms = = 0.0625 mol
they have the same no. of atoms.
statement (3) : wrong. In 1 mole of O2, there are 2 moles of O atoms.
Ans. : B
17. statement (1) : correct.
statement (2) : correct.
statement (3) : wrong. This statement just tells us H2SO4 is a dibasic acid.
Ans. : A
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
18. the chemical equation involved :
CaCO3(s) + 2HCl(aq) CaCl2(aq) + H2O(l) + CO2(g)
no. of moles of CaCO3 = = 0.075 mol
no. of moles of HCl = = 0.1 mol
0.075 mol of CaCO3 require 0.075 2 = 0.15 mol of HCl but there is only 0.1 mol of HCl,
this HCl is limiting.
no. of moles of CO2 = no. of moles of HCl = = 0.05 mol
volume of CO2 = 0.05 24 = 1.2 dm3
Ans. : B
19. experiment (1) : can.
4FeS2(s) + 11O2(g) 2Fe2O3(s) + 8SO2(g)
experiment (2) : can’t. H2SO4(aq) acts as an acid, reacting with reactive metals to give H2(g).
Fe(s) + H2SO4(aq) FeSO4(aq) + H2(g)
experiment (3) : can. H2SO4(l) acts as an oxidizing agent, reacting with metals to give SO2(g).
Cu(s) + H2SO4(l) CuSO4(s) + SO2(g) + 2H2O(l)
Ans. : B
20. 1st statement : wrong.
Since water is not a gas, so its molar volume is not the same as that of a gas,
CO2.
2nd statement : correct.
no. of atoms no. of moles of atoms
no. of moles of atoms in H2O = 3 mol
no. of moles of atoms in CO2 = 3 mol
Ans. : C
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
21. A : wrong.
Zn(s) + H2SO4(aq) ZnSO4(aq) + H2(g)
Zn(s) + 2H2SO4(l) ZnSO4(aq) + SO2(g) + 2H2O(l)
B : wrong. Assume the formula of sugar is C6H12O6.
C6H12O6(s) + H2SO4(aq) no reaction
C6H12O6(s) 6C(s) + 6H2O(l)
C : correct.
2NH3(aq) + H2SO4(aq / l) (NH4)2SO4(aq)
D : wrong. Dilute H2SO4(aq) does not have dehydrating property.
CuSO4nH2O(s) + H2SO4(aq) no reaction
CuSO4nH2O(s) CuSO4(s) + nH2O(l)
Ans. : C
22. The chemical equation involved :
I2(aq) + SO2(g) + 2H2O(l) 2I-(aq) + SO42-(aq) + 4H+(aq)
A : wrong. The colour of iodine solution should change from brown to colourless.
B : wrong. The final products are aqueous solution.
C : wrong. It is a redox reaction.
D : correct. The O.N. of S increases from +4 (in SO2) to +6 (in SO42-).
Ans. : D
23. The chemical equation involved :
Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g)
no. of moles of Zn = = 0.333 mol
no. of moles of HCl = = 0.5 mol
0.333 mol of Zn require 0.333 2 = 0.666 mol of HCl. There is 0.5 mol of HCl only, it is
limiting.
no. of moles of H2 = no. of moles of HCl = = 0.25 mol
volume of H2 = 0.25 24 = 6.0 dm3
Ans. : B
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
24. statement (1) : correct.
Cu(s) + 2H2SO4(l) CuSO4(aq) + SO2(g) + 2H2O(l)
statement (2) : correct.
Density molar mass of gas
Average molar mass of air = 28.8 g mol-1
Molar mass of SO2 = 64.1 g mol-1
statement (3) : correct.
2NaOH(aq) + SO2(g) Na2SO3(aq) + H2O(l)
Ans. : D
25. 1st statement : true. Assume the formula of filter paper is CnH2mOm.
CnH2mOm(s) nC(s) + mH2O(l)
2nd statement : true but it doesn’t explain 1st statement. The reason should be conc. H2SO4
behaves as dehydrating agent, dehydrating filter paper black.
Ans. : B
26. 1st statement : wrong. Volume occupied by a solid and a gas is different.
2nd statement : correct. They have same no. of moles.
Ans. : C
27. the chemical equation involved :
4H2(g) + Fe3O4(s) 3Fe(s) + 4H2O(l)
no. of moles of H2 = = 4.0 mol
no. of moles of Fe = = 3.0 mol
mass of Fe = 3.0 55.8 = 168.0 g = 0.168 kg
Ans. : C
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
28. no. of moles of O2 = =
total no. of atoms = =
Ans. : B
29. statement (1) : correct. It is because H is negative which implies that the reaction is
exothermic, heat is released during reaction.
statement (2) : wrong. The conditions are not included in the equation.
statement (3) : correct. It can be calculated from the stoichiometric constants from the
equation. For the reactants, the total no. of moles is 2 mol (1 mol of H2 + 1 mol
of Cl2). For the products, the total no. of moles is 2 mol.
Ans. : C
30. Ans. : D
31. 1st statement : true. Bromine can react with sodium sulphite but cannot react with sodium
sulphate.
Br2(aq) + SO32-(aq) + H2O(l) 2Br-(aq) + SO4
2-(aq) + 2H+(aq)
2nd statement : true which is the correct explanation for the 1st statement. Bromine is an
oxidizing agent and sodium sulphite is a reducing agent. When they react,
bromine is reduced to bromide ion; while sulphite is oxidized to sulphate.
Ans. : A
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
32. the chemical equation involved :
X(g) + 3Y(g) 2Z(g)
40 cm3 of X should react with 40 3 = 120 cm3 of Y. However, there is only 60 cm3 of Y, thus
Y is limiting and X is in excess.
By Avogadro’s Law,
volume of Z = = 40 cm3
After reaction, 40 – = 20 cm3 of X remains.
Volume of the resultant gaseous mixture = volume of X remained + volume of Z produced
= 20 + 40 = 60 cm3
Ans. : B
33. no. of molecules no. of moles
substance A : = 1.0 mol
substance B : = 0.5 mol
substance C : = 1.059 mol
substance D : = 0.845 mol
Ans. : C
34. Assume the formula of starch is CnH2mOm.
CnH2mOm nC(s) + mH2O(l)
(black substance)
It is due to dehydrating property of conc. H2SO4.
Ans. : A
35. Ans. : B
- 25 -
H2SO4(l)
PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
36. statement (1) : correct. SO2(g) dissolved in water to give H2SO3(aq) which can ionize in water
to give H+ and SO32- ions, which are mobile. Thus the solution is a better
electrolyte than water.
SO2(g) + H2O(l) H2SO3(aq)
H2SO3(aq) 2H+(aq) + SO32-(aq)
statement (2) : correct. SO2(aq) is a reducing agent and Fe2(SO4)3 is an oxidizing agent. Redox
reaction can occur. The ionic equation is as follows :
SO2(aq) + 2Fe3+(aq) + 2H2O(l) SO42-(aq) + 2Fe2+(aq) + 4H+(aq)
statement (3) : wrong. Both SO2(aq) and KBr(aq) are reducing agents. No redox reaction
occurs.
Ans. : A
37. set-up (1) : can.
set-up (2) : can’t. CaO can react with the moist SO2(g).
CaO(s) + SO2(g) CaSO3(s)
set-up (3) : can.
Ans. : B
38. the chemical equation involved :
2NaN3(s) 2Na(s) + 3N2(g)
no. of moles of N2 = = 3 mol
no. of moles of NaN3 = = 2 mol
mass of NaN3 = 2 (23.0 + 14.0 3) = 130.0 g
Ans. : B
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
39. Br2(aq) is an oxidizing agent.
substance A : can. An addition reaction occurs. 1,2-dibromopropane is formed.
(1,2-dibromopropane)
substance B : can. SO2 is a reducing agent.
SO2(g) + Br2(aq) + 2H2O(l) SO42-(aq) + 2Br-(aq) + 4H+(aq)
substance C : KI is a reducing agent.
Br2(aq) + 2I-(aq) 2Br-(aq) + I2(aq)
substance D : can’t. Br2 can’t react with Cl-(aq).
Ans. : D
40. the chemical equation involved :
Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g)
no. of moles of Zn = = 0.02752 mol
no. of moles of HCl = = 0.025 mol
0.02752 mol of Zn has to react with 0.02752 2 = 0.05504 mol of HCl. There is only 0.025
mol of HCl, it is limiting.
no. of moles of H2 = = 0.0125 mol
By Avogadro’s Law,
volume of H2 produced = 0.0125 24.0 = 0.30 dm3
Ans. : A
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
41. Na2SO3(aq) is a reducing agent. It can only reacts with oxidizing agents.
substance A : can. I2 is an oxidizing agent.
I2(aq) + SO32-(aq) + H2O(l) 2I-(aq) + SO4
2-(aq) + 2H+(aq)
substance B : can. KMnO4 / H+ is an oxidizing agent.
2MnO4-(aq) + 5SO3
2-(aq) + 6H+(aq) 2Mn2+(aq) + 5SO42-(aq) + 3H2O(l)
substance C : can’t.
substance D : can. Fe2(SO4)3 is an oxidizing agent.
SO32-(aq) + 2Fe3+(aq) + H2O(l) SO4
2-(aq) + 2Fe2+(aq) + 2H+(aq)
Ans. : C
42. Between Cl2(aq) and SO2(aq), Cl2(aq) bleaches substances through oxidation. The following
chemical equations involved :
Cl2(aq) + H2O(l) HCl(aq) + HOCl(aq)
HOCl(aq) H+(aq) + OCl-(aq)
OCl-(aq) + dye Cl-(aq) + (dye + O)
Ans. : A
43. sentence (1) : correct. Sulphur is a yellow solid under room temperature and pressure.
sentence (2) : wrong. Sulphur is insoluble in water.
sentence (3) : correct. Sulphur is oxidized to SO2, which is in turn further oxidized to SO3. It
dissolved in conc. H2SO4 to give oleum, H2S2O7. Finally, oleum dissolved in
water to give conc. H2SO4.
Ans. : C
44. Ans. : C
- 28 -
PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
45. the chemical equations involved :
CH4(g) + 2O2(g) CO2(g) + 2H2O(l)
2C2H6(g) + 7O2(g) 4CO2(g) + 6H2O(l)
since the mole ratio of CH4 and C2H6 is 1 : 1, thus the volume ratio is also 1 : 1, i.e.
volume of CH4 = 100 cm3 and volume of C2H6 = 100 cm3
Volume of O2 = 200 cm3
Volume of O2 = 350 cm3
Total volume of O2 required = 350 + 200 = 550 cm3
Ans. : B
46. pH value > 7 means the solution is alkaline.
substance (1) : wrong. Cl2(g) dissolved in water to give an acidic solution.
Cl2(g) + H2O(l) HCl(aq) + HOCl(aq)
HCl(aq) H+(aq) + Cl-(aq)
substance (2) : correct. CaO(s) dissolved in water to give calcium hydroxide solution, which is
alkaline.
CaO(s) + H2O(l) Ca(OH)2(aq)
substance (3) : wrong. SO2(g) dissolved in water to give an acidic solution.
SO2(g) + H2O(l) H2SO3(aq)
H2SO3(aq) 2H+(aq) + SO32-(aq)
Ans. : B
47. 1st statement : false. Concentrated H2SO4 is used instead of oleum to absorb SO3(g).
2nd statement : true.
Ans. : C
48. 1st statement : true. SO2(g) is a food preservative and an anti-oxidant.
2nd statement : true. It is the correct explanation of the 1st statement.
Ans. : A
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PRODUCTS FROM IMORTANT PROCESSES Textbook (Book 2) : p.267 – 292
49. A : correct.
2ZnS(s) + 2O2(g, from the air) 2ZnO(s) + SO2(g)
B : correct.
2SO2(g) + O2(g) 2SO3(g)
conditions : 450℃, 1 atm and V2O5 as a catalyst
C : wrong. Concentrated H2SO4 is used instead of water to react with SO3(g).
SO3(g) + H2SO4(l) H2S2O7(l)
D : correct. This process is exothermic, heat is liberated.
Ans. : C
50. Ans. : C
51. the chemical equation involved :
2NaHCO3(s) Na2CO3(s) + CO2(g) + H2O(l)
no. of moles of NaHCO3 =
no. of moles of CO2 formed = = 2
volume of CO2 produced = 2.0 24.0 = 48.0 dm3
Ans. : C
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heating
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