CLASS 10 SCIENCE : CARBON AND ITS COMPOUNDS Question Bank
A. MULTIPLE CHOICE QUESTIONS (MCQs)
20 Questions
1. Carbon generally forms covalent compounds because it
A. easily loses four electrons
B. easily gains four electrons
C. shares electrons to complete its outer shell
D. has no valence electrons
2. The unusually large number of carbon compounds is mainly due to
A. low atomic mass and high density
B. tetravalency and catenation
C. high melting point and conductivity
D. metallic character and ion formation
3. Which of the following contains a double bond between carbon atoms?
A. Ethane
B. Ethene
C. Methane
D. Propane
4. Which compound belongs to the alkyne family?
A. C₂H₆
B. C₂H₄
C. C₂H₂
D. CH₄
5. A compound has molecular formula C₄H₁₀. Two different structures can be obtained from it. These compounds are called
A. isotopes
B. allotropes
C. structural isomers
D. homologues
6. Which functional group identifies an alcohol?
A. –COOH
B. –OH
C. –CHO
D. –Br
7. Which pair represents successive members of the same homologous series?
A. CH₄ and C₂H₄
B. C₂H₆ and C₃H₈
C. C₂H₄ and C₃H₄
D. CH₄ and C₂H₂
8. Which statement about a homologous series is correct?
A. Every member has a different functional group.
B. Successive members differ by –CH₂–.
C. All members have identical molecular masses.
D. Physical properties never change.
9. The reaction in which hydrogen is added to an unsaturated hydrocarbon is called
A. substitution
B. combustion
C. hydrogenation
D. esterification
10. Which catalyst is commonly associated with hydrogenation of vegetable oils?
A. Sodium chloride
B. Nickel
C. Calcium carbonate
D. Sodium hydroxide
11. When methane reacts with chlorine in sunlight, the reaction is an example of
A. addition
B. substitution
C. esterification
D. neutralisation
12. Which observation can indicate incomplete combustion of a carbon compound?
A. Formation of a clean blue flame
B. Formation of soot
C. Absence of heat
D. Formation of only hydrogen
13. Ethanol reacts with sodium to produce
A. oxygen
B. nitrogen
C. hydrogen
D. carbon dioxide
14. Heating ethanol with concentrated sulphuric acid at suitable temperature produces
A. ethane
B. ethene
C. ethanoic acid
D. methane
15. The functional group present in ethanoic acid is
A. –OH
B. –CHO
C. –COOH
D. –Cl
16. When ethanoic acid reacts with sodium hydrogencarbonate, the gas released is
A. H₂
B. O₂
C. CO₂
D. Cl₂
17. The reaction between an alcohol and a carboxylic acid producing an ester is called
A. substitution
B. esterification
C. hydrogenation
D. oxidation
18. The part of a soap molecule that interacts with water is the
A. hydrophobic tail
B. hydrophilic ionic end
C. carbon chain only
D. hydrocarbon core only
19. Soap is less effective in hard water mainly because
A. it evaporates quickly
B. it reacts with calcium and magnesium ions to form scum
C. it cannot form micelles
D. it becomes acidic
20. Which is generally more effective than soap in hard water?
A. Ethanol
B. Detergent
C. Ethanoic acid
D. Methane
MCQ Answer Key
1-C, 2-B, 3-B, 4-C, 5-C,
6-B, 7-B, 8-B, 9-C, 10-B,
11-B, 12-B, 13-C, 14-B, 15-C,
16-C, 17-B, 18-B, 19-B, 20-B
B. FILL IN THE BLANKS
12 Questions
21. Carbon has ______ valence electrons.
22. The ability of carbon atoms to link with one another is called ______.
23. Carbon is ______ valent.
24. Compounds containing only carbon and hydrogen are called ______.
25. Hydrocarbons containing only single carbon-carbon bonds are called ______.
26. Hydrocarbons containing one or more double bonds are called ______.
27. The successive members of a homologous series differ by a ______ unit.
28. The functional group –OH is characteristic of ______.
29. Ethanoic acid is commonly known as ______ acid.
30. Addition of hydrogen to an unsaturated compound is called ______.
31. The spherical clusters formed by soap molecules in water are called ______.
32. The water-attracting end of a soap molecule is called the ______ end.
Answers
- four
- catenation
- tetra
- hydrocarbons
- alkanes
- alkenes
- –CH₂–
- alcohols
- acetic
- hydrogenation
- micelles
- hydrophilic
C. TRUE OR FALSE
10 Questions
33. Carbon normally forms stable compounds by sharing electrons.
34. Carbon has a valency of two.
35. Diamond and graphite have different structures and therefore different physical properties.
36. Ethene is a saturated hydrocarbon.
37. Members of a homologous series have the same functional group.
38. Unsaturated hydrocarbons can undergo addition reactions.
39. Ethanol contains the –COOH functional group.
40. Ethanoic acid reacts with sodium hydrogencarbonate to release carbon dioxide.
41. Soap molecules contain both hydrophilic and hydrophobic parts.
42. Detergents are generally ineffective in hard water.
Answers
- True
- False
- True
- False
- True
- True
- False
- True
- True
- False
D. MATCH THE FOLLOWING
8 Questions
| Column A | Column B |
|---|---|
| 43. Ethene | a. –COOH |
| 44. Ethanol | b. C₂H₄ |
| 45. Ethanoic acid | c. Micelle |
| 46. Alkane | d. –OH |
| 47. Soap cluster | e. Single carbon-carbon bonds |
| 48. Catenation | f. Addition of hydrogen |
| 49. Hydrogenation | g. Carbon-carbon linking |
| 50. Detergent | h. Effective in hard water |
Answers
43-b, 44-d, 45-a, 46-e, 47-c, 48-g, 49-f, 50-h
E. ASSERTION–REASON
8 Questions
For Questions 51–58, choose:
A. Both Assertion and Reason are true, and Reason correctly explains Assertion.
B. Both Assertion and Reason are true, but Reason does not correctly explain Assertion.
C. Assertion is true, but Reason is false.
D. Assertion is false, but Reason is true.
51. Assertion: Carbon forms a very large number of compounds.
Reason: Carbon has tetravalency and strong catenation ability.
52. Assertion: Covalent carbon compounds generally do not conduct electricity well.
Reason: Covalent bonding generally does not produce free ions.
53. Assertion: Graphite conducts electricity.
Reason: Its carbon atoms are arranged in layers.
54. Assertion: Unsaturated compounds are generally more reactive than saturated compounds.
Reason: Unsaturated compounds contain carbon-carbon double or triple bonds.
55. Assertion: Consecutive members of a homologous series have similar chemical properties.
Reason: They contain the same functional group.
56. Assertion: Soap is less effective in hard water.
Reason: Calcium and magnesium ions can form insoluble substances with soap.
57. Assertion: Hydrogenation can convert an unsaturated compound into a saturated compound.
Reason: Hydrogen is added across an unsaturated bond in the presence of a suitable catalyst.
58. Assertion: Ethanoic acid is a carboxylic acid.
Reason: It contains the –COOH functional group.
Answers
51-A, 52-A, 53-B, 54-A,
55-A, 56-A, 57-A, 58-A
F. VERY SHORT ANSWER QUESTIONS
10 Questions
59. What is meant by catenation?
60. Why is carbon called tetravalent?
61. What type of bond is generally formed by carbon in its compounds?
62. Give one example of a saturated hydrocarbon.
63. Give one example of an unsaturated hydrocarbon.
64. What is a functional group?
65. What is the difference between a hydrophilic and a hydrophobic part of soap?
66. Name the gas produced when ethanoic acid reacts with sodium hydrogencarbonate.
67. Name the reaction used to convert an unsaturated hydrocarbon into a saturated one by adding hydrogen.
68. What is the common name of ethanoic acid?
G. SHORT ANSWER QUESTIONS
12 Questions
69. Explain why carbon generally forms covalent bonds instead of forming C⁴⁺ or C⁴⁻ ions.
70. Explain how tetravalency and catenation together make carbon a versatile element.
71. Distinguish between saturated and unsaturated carbon compounds with one example of each.
72. What is a homologous series? State any two of its important characteristics.
73. Explain structural isomerism using C₄H₁₀ as an example.
74. Differentiate between alkanes, alkenes and alkynes on the basis of carbon-carbon bonding.
75. Why do carbon compounds generally have comparatively low melting and boiling points?
76. Why does incomplete combustion sometimes produce a sooty flame?
77. What happens when ethanol is heated with concentrated sulphuric acid? Mention the role of sulphuric acid.
78. Describe the reaction of ethanoic acid with sodium hydroxide and write the chemical equation.
79. Why does ethanoic acid produce carbon dioxide when treated with sodium hydrogencarbonate?
80. Explain why detergents are generally more suitable than soaps for washing with hard water.
H. CONCEPTUAL / APPLICATION-BASED QUESTIONS
8 Questions
81. A student is given two hydrocarbons, C₂H₆ and C₂H₄. How could the student classify them as saturated or unsaturated based on their structures?
82. A cooking vessel becomes black underneath while a gas stove is being used. What does this indicate about combustion? Explain the likely reason.
83. A compound has molecular formula C₃H₆. Without identifying its exact structure, explain why the formula alone is not enough to decide whether it belongs to an alkane or an alkene family.
84. Two organic compounds have the same molecular formula but different arrangements of carbon atoms. What are they called? Why can their properties differ?
85. A soap solution produces very little foam in a sample of groundwater and a curdy material appears. What does this suggest about the water? Explain.
86. Why does shaking or rubbing clothes help soap clean oily dirt more effectively?
87. A student adds ethanoic acid to sodium hydrogencarbonate and observes brisk bubbling. Identify the gas and suggest a simple test to confirm it.
88. An unsaturated vegetable oil is treated with hydrogen in the presence of a suitable catalyst. Predict the broad chemical change and name the reaction.
I. LONG ANSWER / 5-MARK QUESTIONS
8 Questions
89. Explain the versatile nature of carbon under the following headings:
- tetravalency,
- catenation,
- formation of single, double and triple bonds,
- formation of straight, branched and cyclic structures.
90. Explain covalent bonding using carbon as an example. Why do covalent compounds generally have low melting and boiling points and poor electrical conductivity?
91. Explain homologous series in detail. Include:
- definition,
- common functional group,
- difference between successive members,
- similarity in chemical properties,
- gradual change in physical properties.
92. Describe the four important reactions of carbon compounds:
- combustion,
- oxidation,
- addition,
- substitution.
Give one suitable example for each.
93. Describe ethanol under the following headings:
- formula,
- important uses,
- reaction with sodium,
- dehydration reaction,
- role of concentrated sulphuric acid.
94. Explain the important chemical reactions of ethanoic acid with suitable equations:
- reaction with sodium hydroxide,
- reaction with sodium carbonate,
- reaction with sodium hydrogencarbonate,
- reaction with ethanol.
95. Explain the cleansing action of soap using the concept of micelle formation. Clearly distinguish between the hydrophilic and hydrophobic parts of a soap molecule.
96. Compare soaps and detergents with respect to their composition, action in water and behaviour in hard water. Explain why detergents are generally more effective in hard water.
J. CASE-BASED QUESTIONS
Case Study 1 — Carbon’s Versatility
Carbon has four valence electrons and generally forms covalent bonds by sharing electrons. It can bond with other carbon atoms to form chains, branches and rings. It can also form single, double and triple bonds. These features lead to an enormous variety of carbon compounds.
97(a). What is the valency of carbon?
97(b). Name the property responsible for carbon-carbon chain formation.
97(c). Why can carbon form a large variety of structures?
97(d). What is the difference between a saturated and an unsaturated carbon compound?
Case Study 2 — Homologous Series
Consider the alcohols methanol, ethanol, propanol and butanol. They contain the same functional group, show similar chemical behaviour and successive members differ by a –CH₂– unit.
98(a). What type of series is described here?
98(b). What functional group is common to these compounds?
98(c). What is the difference between two consecutive members?
98(d). As molecular mass increases, what general trend is observed in boiling points?
Case Study 3 — Ethanoic Acid
Ethanoic acid is a carboxylic acid. It reacts with bases as well as carbonates and hydrogencarbonates. It also reacts with ethanol to produce an ester.
99(a). Write the formula of ethanoic acid.
99(b). Name the functional group present in it.
99(c). What gas is released when ethanoic acid reacts with sodium hydrogencarbonate?
99(d). What type of compound is produced when ethanoic acid reacts with ethanol?
Case Study 4 — Soap and Hard Water
Soap molecules contain a water-interacting end and an oil-interacting hydrocarbon portion. In water, they can form micelles around oily dirt. Hard water contains calcium and magnesium ions that can react with soap and produce scum.
100(a). What is a micelle?
100(b). Which part of soap interacts with oily dirt?
100(c). Which ions are mainly responsible for the hardness discussed here?
100(d). Why are detergents generally more effective than soaps in hard water?
K. HIGH-ORDER THINKING QUESTIONS
101. Carbon and silicon can both form chains with hydrogen. Why does carbon form a much wider variety of stable compounds?
102. Diamond and graphite are both made only of carbon. Explain why their physical properties can be dramatically different.
103. A compound has a carbon-carbon double bond. Predict whether it is saturated or unsaturated and identify the type of reaction it may undergo with hydrogen.
104. Two compounds belong to the same homologous series but have different molecular masses. Explain why their chemical properties can remain similar while some physical properties change.
105. A student claims that all compounds containing carbon must be organic compounds. Based on the chapter, how would you evaluate this statement?
106. Explain why the formation of micelles is important for removing oily dirt even though oil itself does not dissolve readily in water.
L. COMPETENCY-BASED QUESTIONS
107. A student is given four compounds:
- CH₄
- C₂H₆
- C₂H₄
- C₂H₂
Arrange them into saturated and unsaturated categories and explain the basis of your classification.
108. A laboratory sample contains an alcohol and another sample contains a carboxylic acid. Suggest a chemical observation that can help distinguish them using the reactions discussed in the chapter.
109. A fuel burns with a yellow, smoky flame instead of a clean flame. What does this suggest about the combustion conditions? Explain.
110. A soap solution works well in distilled water but poorly in hard water. Explain this difference using the ions present in hard water.
ANSWER KEY — OBJECTIVE SECTION
MCQs
1-C | 2-B | 3-B | 4-C | 5-C
6-B | 7-B | 8-B | 9-C | 10-B
11-B | 12-B | 13-C | 14-B | 15-C
16-C | 17-B | 18-B | 19-B | 20-B
Fill in the Blanks
- four
- catenation
- tetra
- hydrocarbons
- alkanes
- alkenes
- –CH₂–
- alcohols
- acetic
- hydrogenation
- micelles
- hydrophilic
True/False
- True | 34. False | 35. True | 36. False | 37. True
- True | 39. False | 40. True | 41. True | 42. False
Match the Following
43-b | 44-d | 45-a | 46-e | 47-c | 48-g | 49-f | 50-h
Assertion–Reason
51-A | 52-A | 53-B | 54-A | 55-A | 56-A | 57-A | 58-A