Teachoo Questions

Class 10
Chapter 4 Class 10 - Carbon and its Compounds

## How to find whether hydrocarbons are Alkane, Alkene or Alkyne?

Rule for Alkane :

• If the number of Hydrogen atoms is 2 more than twice the number of carbon atoms, it is an alkane.
• General Formula: C n H 2n+2
•   The formula of Ethane is C 2 H 6 .
• Number of Carbon Atoms=2
• Number of Hydrogen Atoms=2*Carbon atoms+2 = 2*2+2 = 4+2 = 6
• Since the number of Hydrogen atoms is 2 more than twice the number of carbon atoms, it is an alkane.

Rule for Alkene :

• If the number of Hydrogen atoms is exactly equal to double the number of carbon atoms, it is an alkene.
• General Formula: C n H 2
• The formula of Ethene is C 2 H 4 .
• Number of Carbon Atoms=2
• Number of Hydrogen Atoms=2*Carbon Atoms = 2*2 = 4
• Since number of Hydrogen atoms is double number of carbon atoms, it is an alkene

Rule for Alkyne:

• If the number of Hydrogen atoms is 2 less than double the number of carbon atoms, it is an alkyne.
• General Formula: C n H 2n-2
• The formula of Ethene is C 2 H 2 .
• Number of Carbon Atoms=2
• Number of Hydrogen Atoms=2*Carbon Atoms-2 = 2*2-2 = 2
• Since the number of Hydrogen atoms is 2 less than double the number of carbon.

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