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Carbon and its Compounds

Fried Rich Wohler was born at Aschersheim near Frank furt in Germany in 1800 July. His father was educated. So a good library was always available to him.
         He studied Chemistry under the Guidance of Leopald Cmelin and Berzelius. He used to do dangerous experiments also in his boyhood days. Wohler synthesized an organic compound 'Urea' from an inorganic Chemical. He revolutionised the concepts of organic and inorganic Chemistry.
         Earlier to Wohler, there was a concept that compounds like Urea can only be obtained from nature and their synthesis in the laboratories is not possible. Wohler could make it in the laboratory and he gave birth to synthetic organic chemistry. This great scientist died in 1882.

 

KEY WORDS

* Hybridisation

* Allotropy

* Diamond

* Graphite

* Buckminster fullerene

* Nano tubes

* Catenation

* Tetravalency

* Hydrocarbons

* Alkanes

KEY WORDS

* Alkenes

* Alkynes

* Saturated Hydrocarbons

* Unsaturated hydrocarbons

* Functional Group

* Isomerism

* Homologous series

* Nomenclature

* Combustion

* Oxidation

* Addition reaction

* Substitution reaction

* Ethanol

* Ethanoic acid

* Ester

* Esterification

* Saponification

* Micelle

 

KEY WORDS - EXPLANATION

Hybridisation: The re distribution of orbitals of almost equal energy in individual atoms to give equal number of new orbitals with identical properties like energy and shape is called hybridisation.

Allotropy: The property of an element to exist in two or more physical forms having more or less similar chemical properties but different physical properties is called allotropy.
Diamond: Diamond is the crystalline allotropic form of Carbon. In diamond each Carbon atom Under goes in its excited state sp3 hybridisation. Hence each Carbon atom has a tetrahedral environment. Diamond is one of the hardest material known.
Graphite: Graphite forms a two dimensional layer structure with C - C bonds within the layers. There are relatively weak interactions between the layers. In the layer structure, the carbon atoms are in a triogonal planar environment. The layers are separated by a distance of 3.35 Aº. Graphite is used as lubricant and as the 'lead' in pencils.
Buckminster fullerene (60C): Buckminster fullerenes are molecules of varying sizes that are composed entirely of Carbon. The arrangement of these molecules leads to the form of a hollow sphere, ellipsoid or tube depending upon their orientations. Fullerenes are formed when vaporized Carbon condenses in an atmosphere of an inert gas.
Nano tubes: Nano tubes are another allotropic form of Carbon. Nano tubes consist of hexagonal arrays of covalently bonded Carbon atoms, similar to the sheets in Graphite. These sheets are rolled into cylinders. Due to this reason they are called Nano tubes. These are electrical conductors and can be used as molecular wires.

Catenation: If any element forms bonds between its own atoms to give big molecules we call that property as Catenation property.
Tetravalency: If an atom of an element having four electrons in Valence shell, then the Valency is called Tetravalency.
Hydrocarbons: The compounds containing only Carbon and Hydrogen in their molecules are called hydrocarbons.
Alkanes: Hydrocarbons containing only single bonds between Carbon atoms are called alkanes.
Alkenes: Hydrocarbons containing at least one double bond between Carbon atoms are called alkenes.
Alkynes: Hydrocarbons containing at least one triple bond between Carbon atoms are called alkynes.
Saturated Hydrocarbons: The hydrocarbons containing only C - C single bonds are known as saturated hydrocarbons.
Unsaturated hydro carbons: The hydro carbons that contain atleast one double bond (C = C) or contain atleast one triple bond (C  C) between the two carbon atoms are called Unsaturated hydrocarbons.

Functional group: The characteristic properties of an organic compound depend mainly on an atom or group of atoms in its molecule known as the functional group.
Isomerism: The phenomenon of possessing same molecular formula but different properties by the compounds is known as isomerism.
Homologous series: The series of Carbon compounds in which two successive compounds differ by -CH2 unit is called Homologous series.
Nomenclature: The basic idea behind the systematic Nomenclature is that their should be only one name for the given structure through out the world and also there should be only one structure for the given name.
Combustion: The process of burning of Carbon or Carbon compound in excess of Oxygen to give CO2, heat and light is called Combustion reaction.
Oxidation: Oxidation reactions may be carried out using oxidizing agents. Oxidizing agents or oxidants are substances that oxidize other substances. They themselves undergo reduction.
Addition reaction: Unsaturated organic compounds that contain multiple bonds (=,  bonds) like alkenes, and alkynes undergo addition reactions to become saturated. During the reactions addition of the reagent takes place at the double bonded or triple bonded Carbon atoms.

Substitution reaction: A reaction in which an atom or a group of atoms in a given compound is replaced by other atom or group of atoms is called a Substitution reaction.
Ethanol: Ethanol is Ethyl alcohol. It is a colourless liquid with characteristic sweet odour. Pure ethanol boils at 78.3ºC. Pure ethanol is called absolute (100%) alcohol.
Denatured alcohol is ethanol that contains impurities that make it undrinkable.
Ethanoic acid: Ethanoic acid is acetic acid. It is a colourless liquid with characteristic unpleasant odour. It is soluble in water and more acidic than H2O or ethanol, but less acidic than mineral acids. 5% to 8% solution of Acetic acid in water is called Vinegar and is used widely as a preservative in pickles.
Ester: Ethanoic acid (Acetic acid) reacts in the presence of a mineral acid with ethanol to form a compound called ethyl acetate which is known as an Ester.

Esterfication: The reaction between carboxylic acid and an alcohol in the presence of cone. H2SO4 to form a sweet odoured substance, ester with the functional group is called Esterification.
                                                                 
Saponification: 
Alkaline hydrolysis of ester producing soaps is called Saponification.
Micelle: A spherical aggregate of soap molecules in the soap solution in water is called micelle.

 

SYNOPSIS

¤ If Carbon loses four electrons from the outer shell, it has to form C4+ ions. This requires huge amount of energy which is not available normally. Therefore C4+ formation also is a remote possibility.
¤ Carbon is a non-metal. It belongs to the Fourteenth Group or IVA Group in the Modern Periodic Table.
¤ The elements of this group have four electrons in the Valence Shell.
¤ Electronic configuration of Carbon (ground state) 6C: 1s2 2s2 2p2
¤ To get the octet in its outer shell it has to gain four more electrons to form C4-
¤ The electronegativity of Carbon is only 2.5 and its Nucleus has only six protons. Therefore it would be difficult for a nucleus. With six protons to hold ten electrons. Hence Carbon cannot form C4- ions so easily.

¤ Carbon has to satisfy its tetravalency by sharing electrons with the other atoms.
It has to form four covalent bonds either with its own atoms or atoms of other elements.
¤ Electronic Configuration of Carbon (ground state):
      1s2 2s2 2p2  (OR)  1s2s2px1 2py1  2pz0 
      
       
             1s2              2s2               2px      2py       2pz
                      (Carbon ground state)
¤ Electronic Configuration of Carbon: (excited State)
         
             1s2              2s1               2px1    2py1    2pz1
                    (Carbon excited State)

¤ In the excited state carbon atom gets its one of the '2s' electrons to say 2pz.
¤ Now at this state each Carbon atom has four unpaired electrons. It tends to form four Covalent bonds.
¤ The redistribution of orbitals of almost equal energy in individual atoms to give equal number of new orbitals with identical properties, like energy and shape is called Hybridisation. The newly formed orbitals are called Hydrid orbitals.
sp3 Hybridisation: In the excited Carbon atom its one s-orbital (2s) and three p-orbitals (2px, 2py, 2pz) intermix and reshuffle into four identical orbitals known as sp3 orbitals. Thus Carbon atom undergoes sp3 hybridisation.
       
¤ 
When Carbon atom reacts with Hydrogen, four Hydrogen atoms allow their 's' orbitals containing one electron each to overlap the four sp3 orbitals of Carbon atom which are oriented at an angle of 109º28'


sp2 Hybridisation: 
In the formation of Ethene (Ethylene, CH2 = CH2) each Carbon atom in its excited state undergoes sp2 hybridisation by intermixing one s-orbital (2s) and two p-orbitals. (Say 2px and 2py) and reshuffling to form three sp2 orbitals.
¤ Now each Carbon atom is left with one 'p' orbital (say 2p2) unhybridised.
¤ The three sp2 orbitals having one electron each get separated around the nucleus of Carbon atoms at an angle of 120º.

¤ When carbon atom is ready to form bonds one sp2 orbital of one Carbon atom overlaps the sp2 orbital of the other Carbon atom to form sp2 - sp2 sigma (σ) bond. The remaining two sp2 orbitals of each Carbon atom get overlapped by 's' orbitals of two Hydrogen atoms containing unpaired electrons.
        
¤ 
The common name for Ethene is Ethylene.

sp Hybridisation: Each Carbon is only joining to two other atoms rather than four (as in Ethane or Methane) or three (as in Ethene). Here the Carbon atoms hybridise their outer orbitals before forming bonds, this time they only hybridise two of the orbitals.
¤ They use the 's' orbital (2s) and one of the 2p orbitals, but leave the other 2p orbitals unchanged. The new hybrid orbitals formed are called sp hybrid orbitals, because they are made by an 's' orbital and a p-orbital recognising themselves.
¤ In acetylene molecule, there exists a triple bond between two Carbon atoms and the fourth valency of each Carbon atom is satisfied by Hydrogen atoms.
(H -C  C - H).
         

¤ In C2H2 molecule there are two Carbon atoms and two Hydrogen atoms. In excited state each Carbon atom undergoes sp-hybridisation by mixing its one 's' orbital (2s) and one 'p' orbital (2px) and reshuffling to form two identical orbitals known as sp-orbitals.
¤ Allotropes of Carbon: The allotropes of Carbon are:
    1) Amorphous forms        2) Crystalline forms
¤ Coal, Coke, Wood charcoal, Animal Charcoal, Lamp black, Gas Carbon, Petroleum Coke, Sugar Charcoal are different amorphous allotropes of Carbon.
¤ Carbon in solid phase can exist in three crystalline allotropic forms: diamond, graphite and Buckminster fullerene.
¤ Nano tubes are another allotropic form of Carbon discovered in 1991 by Sumio li jima.
¤ F.Wohler (1828) produced an organic compound 'Urea' in the laboratory by heating an inorganic salt 'Ammonium cyanate'.
¤ The peculiar behaviour of carbon is its ability to form longest chains with its own atoms. If any element forms bonds between its own atoms to give big molecules we call that property as catenation property.

¤ Compounds containing only Carbon and Hydrogen in their molecules are called 'hydrocarbons'.
¤ Open chain hydrocarbons are called 'aliphatic hydrocarbons'.
¤ Hydro carbons containing only single bonds between carbon atoms are called 'Alkanes'.
¤ Hydrocarbons containing atleast one double bond between carbon atoms are called Alkenes.
¤ Hydrocarbons containing at least one triple bond between carbon atoms are called Alkynes.
¤ Hydrocarbons containing only C - C single bonds are known as saturated hydrocarbons. All alkanes are saturated hydrocarbons.
¤ The Hydrocarbons that contain at least one double bond (C = C) or contain at least one triple bond (C 

 C) between two Carbon atoms are called unsaturated hydrocarbons.
¤ Compounds containing C, H, X where X represents halogens ( Cl, Br, I atoms) are known as halo hydrocarbons.
¤ The hydrocarbons that contain - OH group are called alcohols.
¤ General formula of alcohols is R - OH where R is alkyle group, CnH2n + 1
¤ The hydrocarbons with functional group -CHO are called aldehydes.

¤ General formula of aldehydes is R - CHO where R is alkyle group and - CHO is a functional group.
¤ Ketones: The hydrocarbons with  
    Functional group are called Ketones.
¤   group is known as Ketone group.
¤ General formula of ketone is  
     R and R' are alkyl groups which may be same or different.
Carboxylic acids: The general molecular formula of carboxylic acid is R - COOH where R is an alkyle group or H atom.
Ethers: Ethers are Carbon compounds related to H2O in such a way that both hydrogen atoms are replace by two alkyl groups which may be the same or different.
Esters: These compounds are derivatives of carboxylic acids. If the Hydrogen atom of - COOH gets replaced by 'R', the alkyl group esters are obtained.

Amines: -NH2 group is called amine group.
¤ The characteristic properties of an organic compound depend mainly on an atom or group of atoms in its molecule known as the functional group.
Isomerism: The phenomenon of possessing same molecular formula but different properties by the compounds is known as isomerism.
Isomers: The compounds that exhibit isomerism are called isomers.
¤ The series of Carbon compounds in which two successive compounds differ by -CH2 unit is called homologous series.
¤ Homologous series of organic compounds have one general formula: Alkanes (CnH2n + 2), Alkynes (CnH2n - 2) Alcohols (CnH2n + 1) OH... etc.
Combustion reactions: Carbon and its compounds burn in the presence of Oxygen or air to give CO2, heat and light.
Oxidation reactions: Oxidation reactions may be carried out using oxidizing agents. Oxidizing agents or oxidants are substances that oxidize other substances. They themselves undergo reduction.

Addition reactions: Unsaturated organic compounds that contain multiple bonds (=,  bonds) like alkenes, and alkynes undergo addition reactions to become saturated.
Substitution reactions: A reaction in which an atom or a group of atoms in a given compound is replaced by other atom or group of atoms is called a substitution reaction.
¤ Alkanes, the saturated hydrocarbons are chemically least reactive. Therefore they are also called paraffins.
¤ The process of conversion of starches and sugars to C2H5OH is called permentation process.
¤ Ethanoic acid is commonly called as acetic acid. 5%-8% solution of acetic acid in water is called vinegar and is used widely as a preservative in pickles.
¤ The strength of acids may be expressed in terms of their pKa values. These values are related to their dissociation in aqueous solutions.
¤ pKa is the negative value of logarithm of dissociation constant of an acid.
¤ The general formula of esters is R - COO - R'. Here R and R' are alkyl groups or phenyl groups.

¤ The reaction between carboxylic acid and an alcohol in the presence of conc. H2SO4 to form a sweet odoured substance, Ester with the functional group
  is called esterfication
¤ Alkaline hydrolysis of tri esters of higher fatty acids producing soaps is called saponification.
¤ Soaps are good cleansing agents.
¤ A true solution is that in which the solute particles dispersed in the solvent are less than 1mm in diameter.
¤ A colloidal solution contains the solute known as 'dispersed phase' with its particles with diameters greater than 1 mm but lesser than 1000 mm in the solvent known as 'dispersion medium'.
¤ A spherical aggregate of soap molecules in water is called micelle.
¤ Soap has one polar end and one non-polar end.
¤ The polar end is hydrophilic in nature and this end is attracted towards the water.
¤ The non-polar end is hydrophobic in nature and it is attracted towards grease or oil on the cloth, but not attracted towards water.

¤ When soap is dissolved in water, its hydrophobic ends attach themselves to dirt and remove it from the cloth.
¤ The hydrophobic end of soap molecules move towards the dirt or grease particles. These ends try to pull out these particles.
¤ The molecules of soap surround the dirt particles at the centre of the cluster and form a spherical structure called micelle.
¤ The micelles remain suspended in water like particles in a colloidal solution.
¤ The various micelles present in water do not come together to form a precipitate as each micelle repels the other because of the ion-ion repulsion.
¤ Thus, the dust particles remain trapped in micelles and are easily rinsed away with water.
¤ Hence soap micelles remove dirt by dissolving it in water.


 

1. Primary Suffixes

Name of Hydrocarbon

Nature of bond

Suffix

Alkane
(CnH2n + 2)

All single bonds

-ane

Alkene
(CnH2n)

one double bond at least
between two Carbon atoms

-ene

Alkyne
(CnH2n - 2)

one triple bond atleast
between two Carbon atoms

-yne

                        Ready made Information in the form of Tables


1. Primary and secondary prefixes and suffixes of some important functional groups.

   Class

     Formula

  Prefix

     Suffix

Acid halides

     -COX
(where x is halogen atom)

halocarbonyl

Carbonal halide

 

    -(C) O-X

 

Oylhalide

Alcohols

     -OH

hydroxy

ol

 

Class

Formula

Prefix

Suffix

Aldehydes

-CHO

formly

Carbaldehyde

 

- (C) HO

OXO

-al

Amides

CONH2

Carbamoyl

Carboxmide

 

-(C) O NH2

OXO

-al

Amines

- NH2

amino

amine

Carboxylic acids

-COOH

Carboxy

Carboxylic acid 

 

-(C)OOH

 

oic acid

 

Ethers

-OR

(R) oxy

 

Esters

-COOR

Oxycarbonyl

(R)...Carboxylate

 

(C)OOR

R-oxycarbonyl

(R)... oate

Ketones

-C = O

OXO

-one

Nitriles

-CN

cyno

-Carbonytrile

 

-(C)N

 

Nitrile

2. Hydrocarbons - Shapes & hybridisation.

Hydrocarbon

General formula

Shape of molecule

Hybridisation of carbon atoms type

Bond angle

Alkane

CnH2n + 2

Tetra hydral

sp3

109º 28'

Alkene

CnH2n

Trigonal plannar

sp2

120º

Alkyne

CnH2n - 2

 

sp

180º

3. Homo logous Series of Alkanes (CnH2n + 2)

Alkane

Molecular
Formula

Strcuture

No. of
atoms

M.P.

B.P.

Density
gml-1 at 20º C

Methane

CH4

H - CH2-H

1

-183ºC

-164ºC

0.55

Ethane

C2H6

H-(CH2)2-H

2

-183ºC

-89ºC

0.51

Propane

C3H8

H-(CH2)3-H

3

-189ºC

-42ºC

0.50

Butane

C4H10

H-(CH2)4-H

4

-138ºC

0ºC

0.58

Pentane

C5H12

H-(CH2)5-H

5

-136ºC

36ºC

0.63

                                             M.P.: Melting Point, B.P.: Boiling Point

4. Homologous Series of Alkenes (CnH2n)

Alkene

Structure

No. of C-atoms

Formula

Ethene

     CH2 = CH2

      2

C2H4

Propene

    CH3-CH = CH2

      3

C3H6

Butene

  CH3-CH2-CH = CH2

      4

C4H8

Pentene

CH3-CH2-CH2-CH = CH2

      5

C5H10

              No. of C-atoms : Number of Carbon atoms
5. Homo logous Series of Alkynes (CnH2n-2)

Alkene

Structure

No. of C-atoms

Formula

Ethyne

HC CH

2

C2H2

Propyne

CH- C CH

3

C3H4

Butyne

CH3 - H2C-C CH

4

C4H6

Pentyne

CH3-CH2-CH2-C CH

5

C5H8

6. Secondary Suffixes

Compound

Symbol

Common formula

Secondary Suffix

Common IUPAC name

Alchols

-OH

ROH

-ol

Alkanol

Ethers

-O-

ROR

-oxy

alkoxy alkane

Aldehydes

-CHO

RCHO

-al

Alkanal

Ketones

-CO-

RCOR

-one

Alkanone

Carboxylic acids

-COOH

RCOOH

-oic acid

Alkanoic acid

Amines

-NH2

RNH2

-amine

Alkanamine

Esters

-COO-

RCOOR

-oate

Alkyl alkanoate

Posted Date : 28-05-2021

గమనిక : ప్రతిభ.ఈనాడు.నెట్‌లో కనిపించే వ్యాపార ప్రకటనలు వివిధ దేశాల్లోని వ్యాపారులు, సంస్థల నుంచి వస్తాయి. మరి కొన్ని ప్రకటనలు పాఠకుల అభిరుచి మేరకు కృత్రిమ మేధస్సు సాంకేతికత సాయంతో ప్రదర్శితమవుతుంటాయి. ఆ ప్రకటనల్లోని ఉత్పత్తులను లేదా సేవలను పాఠకులు స్వయంగా విచారించుకొని, జాగ్రత్తగా పరిశీలించి కొనుక్కోవాలి లేదా వినియోగించుకోవాలి. వాటి నాణ్యత లేదా లోపాలతో ఈనాడు యాజమాన్యానికి ఎలాంటి సంబంధం లేదు. ఈ విషయంలో ఉత్తర ప్రత్యుత్తరాలకు, ఈ-మెయిల్స్ కి, ఇంకా ఇతర రూపాల్లో సమాచార మార్పిడికి తావు లేదు. ఫిర్యాదులు స్వీకరించడం కుదరదు. పాఠకులు గమనించి, సహకరించాలని మనవి.

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