Hydrocarbons are defined as compounds that contain hydrogen and carbon only. They are of several types. For instance, alkanes, alkenes, alkynes, and so on. 

Now, we will talk about all the different topics that fall under this chapter. From classification to all the ways and means that these are prepared, we'll cover it all.

Hydrocarbons can be classified into numerous categories. They are:

• Saturated Hydrocarbons
  Any hydrocarbon that contains a single carbon bond is known as a saturated hydrocarbon. It has a C-C bond.
  Example: Ethane. 

• Unsaturated Hydrocarbons
  Any hydrocarbon that contains multiple bonds is known as an unsaturated hydrocarbon. It has double or triple bonds. Example: ethene and ethyne. 
• Aromatic Hydrocarbons
  All the hydrocarbons that are derivatives of Benzene are known as aromatic hydrocarbons. Example: benzene and aniline.
  
  

• Alicyclic Compounds
  These compounds contain only carbon atoms. They are known as carbocyclic or alicyclic compounds.
  
   

• Heterocyclic Compounds
  These contain ring atoms that are of carbon, nitrogen, and other such atoms. These are known as heterocyclic compounds.
  
   

These are saturated hydrocarbons that contain a single carbon-carbon bond. These are open-chain hydrocarbons. For example methane, ethane, and propane.

They show chain isomerism, position isomerism, and conformational isomerism.

Preparation of Alkanes

1. By Hydrogenation of alkenes and alkynes

2. By Soda lime
Sodium or potassium salts of fatty acids are gone through decarboxylation.

3. By Wurtz Reaction
It increases the length of the carbon chain.

4. By Kolbe's Electrolysis

5. By reduction of alkyl halides
Any reducing agent can be used

6. Clemmenson's Reaction

7. Wolff-Kishnerts Reaction 

Physical Properties

• On branching, the boiling point of alkanes decreases.
• The first of the four members are colourless gas, next thirteen are colourless liquids. The higher members are colourless solids. 
• They are non-polar.
• They are soluble in non-polar solvents and soluble in polar ones.
• If they have an even number of carbon atoms, the higher the melting point.
• If there are an odd number of carbon atoms, the lower the melting point.

Chemical Properties

Addition of Halogens

• Chlorination
  
• Iodination
  
   

2. Combustion
Alkanes emit a lot of heat and that is why alkanes are used as fuels. 

3. Controlled Oxidation

4. Aromatisation  

5. Isomerisation

6. Reaction with Methane  

7. Reaction with Ethane

Alkenes are unsaturated hydrocarbons that are non-cyclic. They are highly reactive. That's why they are also called olefins. 

Example: propene, ethene. 

Preparation of Alkenes

1. From alkynes

 

2. From alkyl halide
3. From vicinal dihalides
4. From alcohols by acidic dehydrogenation

Physical Properties 

• They are mostly similar to alkanes. 
• It differs in polarity.
• It differs in isomerism from alkanes.
• First, three members are gases.
• The higher members are solids. 
• With increasing size, the boiling point of alkenes increases too. 
• They show geometrical and structural isomerism.
  

Chemical Properties 

• Addition of halogens
  

• Addition of halides of hydrogen-like HCl, HI, HBr. They form alkyl halides. 
  HI is the most reactive and HCl is the least reactive. If we add Hbr to unsymmetrical alkenes, it follows Markovnikov's Rule.
  

• Hydration of alkenes
  
• Oxidation
  This is a test for unsaturation. In this, alkenes are added to the aqueous solution of potassium permanganate. They decolourise the solution.  
  
  The addition of acidic KMnO4 or acidic K2Cr2O7 can result in the oxidation of alkenes to ketones or acids.
  
• Ozonolysis
  
  
  
• Polymerization
  
  
• Diels-Alder Reaction  
  
• Reaction with sulphur monochloride
  
  
• Reactions with Ethene 
  
• Substitution Reaction
  
   

These are unsaturated hydrocarbons wherein the position of the triple bond is defined by the presence of Ozone. It is less reactive than alkenes.

Preparation of Alkynes

• From calcium carbide
  
  
  
  
• From vicinal dihalides 
  
• From tetrahalides
  
   

Physical Properties

• With the increase in molar mass, the density, boiling point and melting point increase too.
• They are all odourless and colourless except acetylene.
• First, two members are gases.
• The next eight members are liquids.
• Other members are gases.
• They are not soluble in water.
• They are soluble in organic solvents.

Chemical Properties

• They show electrophilic and neutrophilic reactions.
• Addition of di-hydrogen
  
• Addition of halogens
  
  
• Addition of water
  
• Addition of hydrogen halides
  
  
• Reaction with Arsenic Chloride  
  
• Cyclic Polymerization
  
  
• Oxidation 
  
• Ozonolysis
  
  
• Reaction with Acetylene
  
• Linear polymerization 
  

They are commonly known as arenes. Most of them contain a benzene ring. Aromatic compounds which have benzene rings in them are benzenoids. The ones that do not have that are known as non-benzenoids.

For example,

Preparation of Aromatic hydrocarbons

• Decarboxylation of aromatic acid
  
   

Physical Properties 

• They're usually colourless liquids or solids.
• They're aromatic.
• They are non-polar.
• They can not be mixed with water.
• They are soluble in organic solvents.
• They burn with a sooty flame.

Chemical Properties

• Nitration
  
  
• Sulphonation 
  
• Halogenation
  
• Friedel Crafts' Alkylation Reaction
  
  
• Friedel Crafts' Acetylation Reaction  
  
• Addition Reaction
  

Some polynuclear hydrocarbons contain more than two benzene rings that can become toxic if they are fused. This toxicity can result in cancer-producing capacity. They are formed by the incomplete combustion of materials like coal, tobacco, petroleum, and so on. 

For example, some of the carcinogenic hydrocarbons are as follows:

1. What is hydrocarbon class 11 NCERT?
   Hydrocarbons are compounds that contain hydrogen and carbon together.
   
   
2. How do you study hydrocarbons class 11?
   The best way to study hydrocarbons is to go through every concept like classification of hydrocarbons, alkanes, alkenes, alkynes, aromatic hydrocarbons, and carcinogenicity and toxicity.
   
   
3. What is the classification of hydrocarbons?
   They are classified as saturated hydrocarbons, unsaturated hydrocarbons, aromatic hydrocarbons, and alicyclic hydrocarbons.