Unit 8: Aliphatic Hydrocarbons

What are Aliphatic Hydrocarbons?

Aliphatic Hydrocarbons are organic compounds composed of carbon and hydrogen atoms arranged in straight or branched chains and non-aromatic rings. This unit explores the structure, types, and reactions of aliphatic hydrocarbons, including alkanes, alkenes, and alkynes. Students will learn about the different classes of these hydrocarbons, their properties, and their applications in various chemical processes and industries.

Key Topics in Aliphatic Hydrocarbons:

• Alkanes: Understanding the properties and reactions of alkanes, or saturated hydrocarbons, which contain single bonds between carbon atoms (e.g., methane, ethane, propane).
• Alkenes: Examining the characteristics and reactions of alkenes, or unsaturated hydrocarbons, with at least one double bond between carbon atoms (e.g., ethene, propene, butene).
• Alkynes: Studying the properties of alkynes, or unsaturated hydrocarbons, with at least one triple bond between carbon atoms (e.g., ethyne, propyne).
• Nomenclature: Learning the systematic naming of aliphatic hydrocarbons based on their structure and bonding.
• Reactions: Exploring the common reactions of aliphatic hydrocarbons, including combustion, addition, and substitution reactions.

Benefits of Studying Aliphatic Hydrocarbons:

• Fundamental Knowledge: Provides a thorough understanding of the basic types and reactions of hydrocarbons, which is crucial for more advanced organic chemistry topics.
• Practical Applications: Highlights the importance of aliphatic hydrocarbons in various industries, including fuel, plastics, and chemical synthesis.
• Preparation for Advanced Chemistry: Equips students with essential knowledge for further studies in organic chemistry and related fields.

This unit is essential for understanding the structure and behavior of aliphatic hydrocarbons, offering foundational knowledge that supports advanced study and practical application in chemistry.

1. Preparation of vegetable ghee involves

a. Halogenation
b. Hydrogenation
c. Hydroxylation
d. Dehydrogenation

2. Formula of chloroform is:

a. CH₃Cl
b. CCl₄
c. CH₂Cl₂
d. CHCl₃

3. The presence of a double bond in a compound is the sign of

a. Saturation
b. Unsaturation
c. Substitution
d. None

4. Vinyl acetylene combines with HCl to form

a. Polyacetylene
b. Benzene
c. Chloroprene
d. Divinyl acetylene

5. The addition of unsymmetrical reagent to an unsymmetrical alkene is in accordance with

a. Hund’s rule
b. Markowniko’s rule
c. Pauli Exclusion Principle
d. Aufbau Principle

6. Synthetic rubber is made by polymerization of

a. Chloroform
b. Acetylene
c. Divinyl acetylene
d. Chloroprene

7. B-B’-dichloroethyl sulphide is commonly known as

a. Mustard gas
b. Laughing gas
c. Phosgene gas
d. Bio-gas

8. When methane reacts with Cl2 in the presence of diffused sunlight the products

a. Chloroform only
b. Carbon tetrachloride only
c. Chloromethane and dichloromethane
d. Mixture of a, b, c

9. Which one of the following gases is used for artificial ripening of fruits.

a. Ethene
b. Ethyne
c. Methane
d. Propane

10. Which of the following aliphatic hydrocarbons is an example of an alkene?

a) Methane
b) Ethylene
c) Propane
d) Butane
Answer: b) Ethylene