Question

Give the general formula for the members of the following: a. alkane series b. alkene series c. alkyne series

Short answer

The general formulas are: alkane - \(C_nH_{2n+2}\), alkene - \(C_nH_{2n}\), and alkyne - \(C_nH_{2n-2}\).

Step-by-step solution

Understand the Hydrocarbon Series

Recognize that alkanes, alkenes, and alkynes are series of hydrocarbons with specific characteristics. Alkanes are saturated hydrocarbons (single bonds), while alkenes and alkynes are unsaturated hydrocarbons (double or triple bonds).

Identify the Alkane General Formula

The general formula for alkanes is derived from their structure of single bonds between carbon atoms. The formula can be written as: \(C_nH_{2n+2}\) where n is the number of carbon atoms.

Identify the Alkene General Formula

The alkenes contain at least one double bond between carbon atoms. The general formula for alkenes is: \(C_nH_{2n}\) where n is the number of carbon atoms.

Identify the Alkyne General Formula

The alkynes contain at least one triple bond between carbon atoms. The general formula for alkynes is: \(C_nH_{2n-2}\) where n is the number of carbon atoms.

Key concepts

alkane general formula

Alkanes are the simplest type of hydrocarbons. These molecules are made up entirely of carbon and hydrogen atoms.
Alkanes are known as saturated hydrocarbons because they only have single bonds between carbon atoms. This means each carbon atom is bonded to as many hydrogen atoms as possible.
The general formula for alkanes is:
\[ C_nH_{2n+2} \]
where

• \( n \) represents the number of carbon atoms in the molecule.

This formula shows that for every 'n' carbon atoms, there are

• \( 2n+2 \) hydrogen atoms.

As an example, for an alkane with

• 3 carbon atoms

the molecular formula would be

• \( C_3H_8 \).
  

Examples of alkanes include methane (

• \( CH_4 \)) and ethane (
• \( C_2H_6 \).
  )

alkene general formula

Alkenes are hydrocarbons containing at least one double bond between carbon atoms. This double bond makes alkenes unsaturated, meaning they have fewer hydrogen atoms than alkanes.
The general formula for alkenes is:
\[ C_nH_{2n} \]
where

• \( n \) represents the number of carbon atoms.

In this formula, for each

• 'n' carbon atoms, there are
• \( 2n \) hydrogen atoms.

For example, if an alkene has

• 3 carbon atoms, the molecular formula would be
• \( C_3H_6 \).
  

Examples of common alkenes are ethene (

• \( C_2H_4 \))
• and propene (\( C_3H_6 \).
  )

alkyne general formula

Alkynes are hydrocarbons that contain at least one triple bond between carbon atoms. This triple bond gives alkynes even fewer hydrogen atoms compared to alkanes and alkenes, making them unsaturated.
The general formula for alkynes is:
\[ C_nH_{2n-2} \]
where

• \( n \) stands for the number of carbon atoms.

According to this formula, for every

• 'n' carbon atoms, there are
• \( 2n-2 \) hydrogen atoms.

For example, if an alkyne has

• 4 carbon atoms, its formula would be
• \( C_4H_6 \).
  

Common examples of alkynes include ethyne (

• \( C_2H_2 \))
• and propyne (\( C_3H_4 \).
  )