Wednesday, 14 June 2017

Functional Groups

Functional group is an atom or group of atoms in a organic molecule that predicts or identifies the characteristics chemical and physical properties of  organic molecule.In short functional groups determine the identity of organic molecules

Explanation:

Functional groups are very important in organic chemistry since they are used to determine the type these molecules and therefore, depict the  of them.

For example,
  •  Hydroxy groups OH, is specific for alcohols. the general structure for alcohols is ROH.

 In a similar way,
  •  COOH is the functional group for carboxylic acids with a general structure RCOOH.

  • For esters, the functional group is COOR', where esters have the general structure RCOOR'.
  And so on.
with different functional groups, alcohols, carboxylic acids, and esters have different chemical and physical properties and therefore, different identity.

Importance of Functional groups in Organic Chemistry:

Functional group is important in organic chemistry for the following three Basic reasons:
  1. They serve as a basic for nomenclature (naming) of organic compounds.
  2. They serve to classify organic compounds in classes/families.All compound with same functional group belong to same class.
  3. A functional group is a site of chemical reactivity in a molecule containing the functional group.


Let us take a specific example; Propane CH3CH2CH3.
 Propane is a gaseous molecule at room temperature. Adding a hydroxy group to its structure we get CH3CH2CH2OH" which is the propanol. Propanol is liquid at room temperature ( change on physical property ). Propanol can react thanks to the presence of the oxygen atom in its backbone, however, propane has very limited reactivity ( change on chemical property ).
There are many other functional groups such as:
Sulfides: RSR'
Thiols: RSH
Ethers: ROR'
Anhydrides: RCOOCOR' Ketones: RCOR'
Aldehydes: RCOH
Amides: RCON(R')2 or RCONH2 or RCONHR'
Amines: RNH2 or RNHR' or RN(R')2
Nitriles: RCN
Alkyl halides: RX where X is an element from group 17.
Alkenes: RCH=CHR'
Alkynes: RCCR'

Functional Groups

F unctional group is an atom or group of atoms in a organic molecule that predicts or identifies the characteristics chemical and physical...