Unsaturated hydrocarbon
Encyclopedia
Unsaturated hydrocarbons are hydrocarbon
s that have double or triple covalent bond
s between adjacent carbon
atom
s. Those with at least one double bond are called alkene
s and those with at least one triple bond are called alkyne
s. Each double bond is represented by a number preceding the name of the base chain, representing on which hydrocarbon in the chain the double or triple bond can be found. Alkenes and alkynes with more than one double or triple bond respectively are named with the appropriate numeric prefix preceding the -ene or -yne
.
Examples of unsaturated hydrocarbon include 2,4-pentadiene and 2-butyne, among others.
Unsaturated hydrocarbons with both double and triple bonds have the suffix -enyne and are handled in a similar manner.
The physical properties of unsaturated hydrocarbons are very similar to those of the corresponding saturated compounds. They are slightly soluble in water.
Except for aromatic compounds, unsaturated hydrocarbons are highly reactive and undergo addition reaction
s to their multiple bonds. Typical reagents added are hydrogen
halide
s, water
, sulfuric acid
, elemental halogen
s and alcohols.
is unsaturated you should add bromine water. If the bromine water becomes decolourised (Goes colorless) then it is unsaturated.
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
s that have double or triple covalent bond
Covalent bond
A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding....
s between adjacent carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
atom
Atom
The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...
s. Those with at least one double bond are called alkene
Alkene
In organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...
s and those with at least one triple bond are called alkyne
Alkyne
Alkynes are hydrocarbons that have a triple bond between two carbon atoms, with the formula CnH2n-2. Alkynes are traditionally known as acetylenes, although the name acetylene also refers specifically to C2H2, known formally as ethyne using IUPAC nomenclature...
s. Each double bond is represented by a number preceding the name of the base chain, representing on which hydrocarbon in the chain the double or triple bond can be found. Alkenes and alkynes with more than one double or triple bond respectively are named with the appropriate numeric prefix preceding the -ene or -yne
-yne
The suffix -yne is used in organic chemistry to form names of organic compounds containing the -C≡C- group, known generally as alkynes. Sometimes a number between hyphens is inserted before it to state which atoms the triple bond is between. This suffix arose as a collapsed form of the end of the...
.
Examples of unsaturated hydrocarbon include 2,4-pentadiene and 2-butyne, among others.
Unsaturated hydrocarbons with both double and triple bonds have the suffix -enyne and are handled in a similar manner.
The physical properties of unsaturated hydrocarbons are very similar to those of the corresponding saturated compounds. They are slightly soluble in water.
Except for aromatic compounds, unsaturated hydrocarbons are highly reactive and undergo addition reaction
Addition reaction
An addition reaction, in organic chemistry, is in its simplest terms an organic reaction where two or more molecules combine to form a larger one....
s to their multiple bonds. Typical reagents added are hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
halide
Halide
A halide is a binary compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative than the halogen, to make a fluoride, chloride, bromide, iodide, or astatide compound. Many salts are halides...
s, water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
, sulfuric acid
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...
, elemental halogen
Halogen
The halogens or halogen elements are a series of nonmetal elements from Group 17 IUPAC Style of the periodic table, comprising fluorine , chlorine , bromine , iodine , and astatine...
s and alcohols.
Testing
To test whether the hydrocarbonHydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
is unsaturated you should add bromine water. If the bromine water becomes decolourised (Goes colorless) then it is unsaturated.