Here are 20 multiple-choice questions (MCQs) related to polyhalogen compounds in the context of haloalkanes for Class 12, without the answers:
MCQs on Polyhalogen Compounds (Haloalkanes)
1. Which of the following is a characteristic of polyhalogen compounds?
A) They contain only one halogen atom B) They contain multiple halogen atoms
C) They are always gaseous D) They are not reactive
2. The reactivity of polyhalogen compounds generally decreases with:
A) Increasing number of halogens B) Decreasing number of halogens
C) Increasing molecular weight D) Decreasing molecular weight
3. Which of the following is an example of a polyhalogen compound?
A) Chloroform B) Carbon tetrachloride C) Iodoform D) All of the above
4. Which of the following is the general formula for polyhalogen compounds?
A) CnH2n+1X B) CnH2nX2 C) CnXn D) CnH2nX3
5. What is the primary use of dichloroethane?
A) Solvent in organic reactions B) Refrigerant C) Pesticide D) Fuel additive
6. Which of the following compounds is used as a dry cleaning solvent?
A) Ethyl bromide B) Carbon tetrachloride C) Chloroform D) All of the above
7. The process of substituting halogen atoms in haloalkanes with hydroxyl groups to form alcohols is called:
A) Halogenation B) Hydrolysis C) Oxidation D) Reduction
8. Which of the following reactions is characteristic of polyhalogen compounds?
A) Electrophilic substitution B) Nucleophilic substitution
C) Free radical substitution D) Addition reactions
9. Which polyhalogen compound is known for its use as a solvent and in the production of Teflon?
A) Trichloroethylene B) Carbon tetrachloride
C) Tetrachloroethylene D) Dichloromethane
10. The compound known as "dichloroethane" is also commonly referred to as:
A) Ethylene dichloride B) Methylene chloride
C) Bromoethane D) Chloroethane
11. Which of the following polyhalogen compounds is commonly used in refrigeration?
A) Trichlorofluoromethane B) Ethyl chloride
C) Iodoform D) Bromoform
12. Polyhalogen compounds are primarily produced by which type of reaction?
A) Combustion B) Halogenation of alkanes
C) Hydrolysis D) Dehydrogenation
13. Which of the following is a common property of polyhalogen compounds?
A) High boiling points B) High solubility in water
C) Low density D) High volatility
14. Which compound is often used as a fumigant and insecticide?
A) Methyl bromide B) Chloroform
C) Carbon tetrachloride D) Bromoform
15. The term "haloalkane" refers to:
A) Alkanes with one halogen atom B) Alkanes with multiple halogen atoms
C) Alkenes with halogen atoms D) Alkynes with halogen atoms
16. Which of the following halogens is not typically found in polyhalogen compounds?
A) Fluorine B) Chlorine C) Bromine D) Oxygen
17. The stability of polyhalogen compounds generally increases with:
A) Increasing electronegativity of halogens B) Decreasing electronegativity of halogens
C) Increasing molecular size D) Decreasing molecular size
18. Which of the following compounds is a tri-iodo compound?
A) Iodoform B) Trichloroethylene C) Carbon tetraiodide D) Bromoform
19. The bond dissociation energy generally increases with:
A) Increasing atomic size of halogens B) Decreasing atomic size of halogens
C) Increasing number of halogen atoms D) Decreasing number of halogen atoms
20. Which of the following compounds is commonly used as a solvent in organic synthesis?
A) Chloroform B) Sodium chloride C) Potassium bromide D) Acetic acid
Feel free to use or modify these questions as needed!
Here are the answers to the multiple-choice questions (MCQs) on polyhalogen compounds in haloalkanes for Class 12, along with explanations for each answer:
Answers and Explanations
1. B) They contain multiple halogen atoms
Reason: Polyhalogen compounds are defined by the presence of more than one halogen atom in their structure.
2. A) Increasing number of halogens
Reason: As the number of halogen atoms in a compound increases, the steric hindrance and electronic repulsion typically make the compound less reactive.
3. D) All of the above
Reason: Chloroform, carbon tetrachloride, and iodoform are all examples of polyhalogen compounds, as they each contain multiple halogen atoms.
4. B) CnH2nX2
Reason: This formula represents polyhalogen compounds where "X" is a halogen and "n" is the number of carbon atoms, indicating that two halogen atoms are present.
5. A) Solvent in organic reactions
Reason: Dichloroethane is widely used as a solvent for various organic reactions due to its ability to dissolve a wide range of organic compounds.
6. B) Carbon tetrachloride
Reason: Carbon tetrachloride is commonly used as a dry cleaning solvent due to its effective ability to dissolve oils and fats.
7. B) Hydrolysis
Reason: Hydrolysis refers to the reaction where water (or hydroxyl groups) substitutes halogen atoms in haloalkanes, forming alcohols.
8. B) Nucleophilic substitution
Reason: Polyhalogen compounds primarily undergo nucleophilic substitution reactions, where nucleophiles replace the halogen atoms.
9. C) Tetrachloroethylene
Reason: Tetrachloroethylene, also known as perchloroethylene, is used as a solvent and in the production of Teflon.
10. A) Ethylene dichloride
Reason: Dichloroethane is also known as ethylene dichloride, highlighting its two chlorine substituents on the ethylene molecule.
11. A) Trichlorofluoromethane
Reason: Trichlorofluoromethane, commonly known as CFC-11, was widely used in refrigeration systems.
12. B) Halogenation of alkanes
Reason: Polyhalogen compounds are typically formed through the halogenation process, where alkanes react with halogens to substitute hydrogen atoms with halogen atoms.
13. A) High boiling points
Reason: Polyhalogen compounds tend to have higher boiling points due to the presence of multiple halogen atoms, which increases the molecular weight and intermolecular forces.
14. A) Methyl bromide
Reason: Methyl bromide is commonly used as a fumigant and insecticide, particularly in agriculture.
15. A) Alkanes with one halogen atom
Reason: The term "haloalkane" refers to alkanes that have at least one halogen atom bonded to them, distinguishing them from polyhalogen compounds.
16. D) Oxygen
Reason: Oxygen is not a halogen; the halogens include fluorine, chlorine, bromine, and iodine.
17. C) Increasing molecular size
Reason: As the size of the molecules increases, the bond strengths generally become weaker for the halogens, making the polyhalogen compounds more stable.
18. A) Iodoform
Reason: Iodoform (CHI₃) is an example of a tri-iodo compound, containing three iodine atoms attached to a carbon atom.
19. B) Decreasing atomic size of halogens
Reason: Bond dissociation energy typically increases with smaller halogen atoms due to stronger bonds formed with carbon, leading to more stable polyhalogen compounds.
20. A) Chloroform
Reason: Chloroform is commonly used as a solvent in organic synthesis due to its excell
ent solvent properties for organic compounds.
Feel free to ask if you need further clarification or more questions!
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