The compounds which are formed by the combination of carbon and hydrogen are called hydrocarbons.

Its examples are:

1. Methane (CH₄)
2. Ethane (C₂H₆)
3. Ethene (C₂H₄)

Hydrocarbons in which carbon atoms are connected by a single covalent bond are called saturated hydrocarbons.
For eg. Methane, ethane, propane, etc.
Hydrocarbons in which carbon atoms are connected by the multiple covalent bond are called unsaturated hydrocarbons.
Foe eg. Ethene, ethyne.

The saturated hydrocarbons in which all carbon atoms are connected by a single covalent bond is called alkanes.
Any three examples are:
Methane (CH₄)
Ethane (C₂H₆)
Pentane (C₅H₁₂)

The unsaturated hydrocarbons in which any two carbon atoms are connected by a double covalent bond are called alkenes.
Eg. (ene groups)
Methene, Ethene, etc.
The unsaturated hydrocarbons in which any two carbon atoms are connected by a triple covalent bond are called alkynes.
Eg. (ene groups)
Methyne, Ethyne, etc.

A functional group is an atom or group of atoms that determines the chemical properties of a hydrocarbons.
For example:
Ether ( - 0 - )
Aldehyde ( - CHO )

a. Saturated hydrocarbon having three carbon atoms.
Name: Propane
Formula: C₃H₈
b. An alkene having four carbon atoms.
Name: Butene
Formula: C₄H₈
c. An alkyne having two carbon atoms.
Name: Ethyne
Formula: C₂H₂

The group organic compounds having similar structure and chemical properties in which the successive compounds differ by - CH₂ group is called homologous series.
The first five members are:
Methane ( CH₄ )
Ethane ( C₂H₆ )
Propane ( C₃H₈ )
Butane ( C₄H₁₀ )
Pentane ( C₅H₁₂ )

a. Methane.
It occurs in gaseous state at room temperature.
Its two uses are:
> It is used in laboratory.
> It is used to make printing ink and paints.
b. Ethane.
It occurs in natural gas and petroleum mines.
Its two uses are:
> It is used as the source of heat.
> It is used for making shoe polish, ink, etc.
c. Propane.
It occurs in natural gas and petroleum mines in the form of saturated hydrocarbon.
Its two uses are:
> It is used in laboratory.
> It is...

Isomers are organic compounds having the same molecular formula but a different structure and properties.
Isomerism is the existence of two or more different organic compounds having the same molecular formula but different structure and properties.
The possible isomers of pentane are:
n-pentane
iso-pentane

Alcohols are organic compound which contains hydroxyl group (OH). Its types are:
> Monohydric alcohol ---------> Methanol
> Dihydric alcohol ---------> Ethylene glycol
> Trihydric alcohol ----------> Glycerol

Structural formula:
Condensed formula: CH₂OH - CHOH - CH₂OH
Its three uses are:
> It is used as sweetening agent of confectionery.
> It is used in lip guards, face cream, etc.
> It is used for preservation of fruits and tobacco.

An organic compound having oxygen in between two alkyl groups is called ether.
Structural formula of dimethyl ether.

Structural formula of diethyl ether.

Any three uses of ether are listed below:
> It is used as organic solvent.
> It is used for purification of organic compounds.
> It is used as refrigerant for cooling purpose.

a. Saturated and unsaturated hydrocarbons.

We all know that, propane contains all the carbon atoms that are connected by a single covalent bond. It is chemically less reactive so, it is called a saturated hydrocarbon.

We all know that alkanes are chemically less reactive. Here, para means less and affins means reactivity. So, alkanes are also called paraffins.

We all know that, butene contains two carbon atoms connected each other with double covalent bond. It is chemically more reactive also. So, it is called unsaturated hydrocarbons.

We know that, methane is formed by the decomposition of organic matter within water in marshy places. So, it is called marsh gas.

Propyne.
> It is unsaturated hydrocarbon.

Name: Propane
Structural formula:

a. Ethane.
> It is used in laboratory.
> It is used as source of heat.
b. Ethyl alcohol.
>It is used in laboratory.
> It is used as a fuel.
c. Diethyl ether.
> It is used as organic solvent.
> It is used as purification if organic compounds.

Name: Glycerol
Structural formula:

Glucose is a white crystalline powder which dissolves in water easily.
Its chemical formula is C₆H₁₂O₆.
Its function in our body are:
- It helps our body to produce APT.
- It helps to transport free sugar in the blood.
- It provides energy inside cell if living body.
- It plays vital role in metabolism.

High sugar level in the blood of human beings causes swelling of different body parts. It also increases the chance of obesity.