Hydrocarbons – Important NEET Concepts, Reactions & Questions
Author: Chemistry of Science | Category: Organic Chemistry | Level: NEET / Class 11
Introduction to Hydrocarbons
Hydrocarbons are organic compounds made up of carbon and hydrogen atoms. They form the basic framework for organic chemistry and are classified into various types based on the presence of single, double, or triple bonds.
Classification of Hydrocarbons
1. Alkanes (Saturated Hydrocarbons)
Alkanes contain single covalent bonds between carbon atoms. Their general formula is CnH2n+2. Example: Methane (CH₄), Ethane (C₂H₆).
2. Alkenes (Unsaturated Hydrocarbons)
Alkenes contain at least one double bond. Their general formula is CnH2n. Example: Ethene (C₂H₄), Propene (C₃H₆).
3. Alkynes (Triple Bond Hydrocarbons)
Alkynes contain one or more triple bonds. The general formula is CnH2n−2. Example: Ethyne (C₂H₂).
IUPAC Nomenclature Rules
Step 1: Identify the Longest Carbon Chain
This becomes the parent chain. Example: 6-carbon chain = Hexane.
Step 2: Number the Chain
Number the chain such that substituents get the lowest possible numbers.
Step 3: Add Prefixes and Suffixes
Use prefixes for side chains (like methyl, ethyl) and suffixes (-ane, -ene, -yne) for bond type.
Important Hydrocarbon Reactions
1. Combustion Reaction
Complete oxidation of hydrocarbons in oxygen produces CO₂ and H₂O with energy release.
2. Substitution Reaction
In alkanes, hydrogen atoms can be substituted by halogens using sunlight or UV light.
3. Addition Reaction
Unsaturated hydrocarbons like alkenes and alkynes undergo addition of hydrogen, halogens, or water.
4. Elimination Reaction
Involves removal of small molecules (like H₂O or HCl) forming double or triple bonds.
Important NEET Questions on Hydrocarbons
Q1. Which of the following is an example of an unsaturated hydrocarbon?
Answer: Ethene (C₂H₄) – contains a double bond.
Q2. Write the general formula of Alkanes.
Answer: CnH2n+2
.Q3. Name the product formed when ethene reacts with bromine.
Answer: 1,2-Dibromoethane (Addition Reaction).
Tips to Remember for NEET Chemistry
- Learn all IUPAC naming rules by practicing examples daily.
- Focus on mechanism patterns like substitution, addition, and elimination.
- Revise reaction conditions and catalysts.
- Use short notes and flashcards for revision.
Download Free Hydrocarbon Notes PDF
📥 Download PDF NotesConclusion
Hydrocarbons are the foundation of organic chemistry and are highly important for NEET aspirants. With proper understanding of reactions, mechanisms, and nomenclature, scoring in this chapter becomes easy. Keep revising and solving previous year questions regularly.
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