Carbon and its Compounds

Allotropy:Allotropy is the property of an element to exist in more than one physical forms having similar chemical properties but different physical properties. Carbon exists both in crystalline and amorphous allotropic forms.

Crystalline allotropes of carbon:DiamondGraphite Fullerene 

Amorphous  allotropes of carbon:CoalCokeCharcoalLampblackGas carbonCoke 

Diamond:        •  Diamond is a rigid, compact, three dimensional structure.        •  Diamond is very hard to break.        •  Diamond is bad conductor of heat and electricity. Because in diamond each carbon is bonded to four other carbon atoms. There are no free electrons present in it.        •  Diamond are not attacked by acids, bases and other reagents but it can reacts with fluorine to form carbon tetrafluoride at about 1023 K temperature.           C + 2F2  → CF4        •  Diamond burns in air at about 1173 K to produce carbon dioxide gas.        •  In diamond carbon atoms are in  tetrahedral arrangement.

Uses:Diamonds are used in glass cuttings and in making drills.

Because of reflection property it is used as gem  in jewellery.

Graphite:        •  Graphite contains carbon atoms in hexagonal rings, which are joined to form layers.        •  The layers of carbon can slide over each other.Graphite is a good conductor of heat and electricity. Since graphite contains free electrons, it is a good conductor of heat and electricity.        •  Graphite burns in air at about 973 K to produce carbon dioxide gas.

Uses:Since graphite is a good conductor of electricity it is used as electrode.Graphite is used as moderator in nuclear reactors.It is also used as solid lubricant in machines.

Fullerenes :        •  Fullerene was discovered in the year 1985.        •  C60 is the very popular and stable form of the known fullerenes. This consists of 60 carbon atoms arranged in pentagons and hexagons, like in a standard football.        •  Fullerenes are also called Buckminsterfullerenes as they are shaped like the geodesic dome designed and built by the US architect Buckminster fuller.        •  Fullerenes are prepared from graphite at higher temperatures.        •  There exists other members of fullerenes like C70, C84...etc

In general carbon involves in covalent bonding.

Covalent bond:A bond formed by the sharing of valence electrons between atoms of similar electronegativity is called covalent bond.

Properties of covalent compounds:Covalent compounds have low melting and boiling points.Covalent compounds are non conductors of electricity this is due to the absence of free ions.

Classification of covalent bonds:Based on the number electrons shared between the atoms, the covalent bond is classified into three types. They are: • Single covalent bond • Double covalent bond • Triple covalent bond

Single Covalent Bond: Single covalent bond is formed by sharing a single pair of electrons. Example: H2 (H - H)

Hydrogen has one electron and it requires one more electron to attain the nearest inert gas configuration. To achieve this each hydrogen atom contributes an electron to form a single bond. Thus, a single covalent bond is formed between the two atoms of the hydrogen molecule.

Double Covalent Bond: Double bond is formed by the sharing of two pairs of electrons of the valence shell.

Example: Oxygen molecule (O = O)The atomic number of oxygen is 8. It requires two electrons to achieve the nearest stable inert gas configuration, which is neon. To achieve this, two oxygen atoms contribute two unpaired electrons to produce two bond pairs. Thus, they

share these two electron pairs to form a double bond

Triple Covalent Bond: Triple bond is formed by sharing of three pairs of electrons of the valence shell. Example : Nitrogen molecule (N ≡ N).The atomic number of nitrogen is 7. It requires 3 more electrons for attaining the nearest inert gas (neon) configuration. Thus, 2 nitrogen atoms combine together and produce 3 bond pairs and share the three bond pairs between them.

Representation of a Bond:Bond formation can be represented using Lewis structures. The Lewis dot structures provide a picture of the bonding in molecules in terms of the shared pairs of electrons and the octet rule. Example: Lewis dot structures of CCl4 and CH4.

Bond Formation in Carbon:From the electronic configuration of carbon, it is clear that it has to either gain or lose four electrons, to attain noble gas configuration.If carbon gains four electrons it would form a c-4 ion. It is unable to hold four extra electrons. It would be difficult for the six protons to hold the ten electrons.

Formation of C+4 is difficult as it requires high amount of energy which leaves six protons in the nucleus and holding only two electrons.Thus formation of both C-4 and C+4 forms is difficult.

Carbon overcomes this difficulty by sharing its electrons with other atoms of carbon or with atoms of other elements. sharing of electrons results in a covalent bond and the shared electrons belong to either of the atoms, this sharing helps in achieving noble gas configuration.

Covalent Bond Formation in Methane:During the formation of a methane molecule carbon atom share its four valence electrons with four hydrogen atoms. Thus in methane molecule there exists four single bonds between carbon and four hydrogen atoms.

Double bond formation of Carbon:Carbon can involve in double bonding either with it self or with other atoms like Oxygen.Example: Formation of CO2: Carbon shares its four valence electrons with two oxygen atoms. Thus carbon forms two double bonds with two oxygen atoms.

Triple bond formation of Carbon:Carbon can involve in triple bonding either with it self or with other atoms like Nitrogen.Example: Formation of HCN: Carbon shares three of its valence electrons with one nitrogen atom to form triple bond with it. And shares one electron with one hydrogen to form single bond with it.

The existence of such a large number of organic compounds is due to the unique properties of carbon.The unique properties of carbon are:        → Tetra valency        → Catenation        → Formation of multiple bonds

Tetravalency:Carbon shares its four valence electrons with other atoms and forms four single covalent bonds to get nearest noble gas formation. This is known as tetravalency.

Catenation:The property of self linkage among identical atoms to form long chain compounds is known as catenation. Carbon exhibits maximum catenation, when compared to elements like sulphur and silicon, due to strong carbon-carbon bonds and tetra valency. Due to this catenation, carbon atoms can form various types of straight chains, branched chains and ring structures.

Formation of multiple bonds:Carbon atoms are capable of forming multiple bonds with other carbon atoms.

 Hydrocarbons:All the carbon compounds which contain just carbon and hydrogen are called hydrocarbons.

Classification of hydrocarbons:Hydrocarbons are broadly divided into two groups.        •  Open chain hydrocarbons        •  Cyclic or closed chain hydrocarbons

Open chain hydrocarbons:Open chain hydrocarbons contain carbon-carbon straight chains. They are further classified into two types.        •  Saturated hydrocarbons        •  Unsaturated hydrocarbons.

Saturated hydrocarbons or Alkanes: Saturated hydrocarbons are straight chain compounds containing only single covalent bonds. These are also known as alkanes. General formula of alkanes is CnH2n+2.Example: Methane, ethane, propane, butane... etc.

 Unsaturated hydrocarbons:Unsaturated hydrocarbons are the straight chain compounds containing double or triple covalent bonds.Unsaturated hydrocarbons are classified into two types. They are alkenes and alkynes.

Alkenes:Hydrocarbons with a double bond between carbon atoms are known as alkenes.General formula of alkenes is CnH2n. Example: Ethene, propene, butene...etc

Alkynes:Hydrocarbons with triple bonds between carbon atoms are known as alkynes. General formula of alkynes is CnH2n-2.

Example: Ethyne, propyne...etc

 

Cyclic or closed chain hydrocarbons: The compounds of carbon which contain a closed ring of carbon atoms are called as cyclic hydrocarbons. They are of two types.        •  Alicyclic hydrocarbons         •  Aromatic hydrocarbons

Alicyclic Hydrocarbons:Alicyclic hydrocarbons are in the form of a carbon cycle. They contain three or more carbon atoms. Example: Cyclopropane, Cyclo butane.

Alicyclic compounds does not follow Huckel's rule. Aromatic Hydrocarbons:The cyclic compounds which contain a single and a double bond at alternate positions and exhibit special properties are known as aromatic compounds. Huckel's rule (4n+2 rule): According to Huckel’s rule the hydrocarbons which contains 4n+2 (where n = 0,1,2,3,…etc) number of delocalized pi electrons which are present in a ring structure are called aromatic compounds. Example:Benzene: Benzene (C6H6) containing a six membered carbon ring with alternate single and double bonds is an aromatic compound.

Homologous Series:A series of organic compounds with the same general formula but differ from adjacent members by "-CH2-" group are referred to as homologous series of compounds.Example: Homologous series of alcohols:

CH3 - OH : MethanolCH3-CH2-OH : EthanolCH3-CH2-CH2-OH : PropanolCH3-CH2-CH2-CH2-OH : Butanol

The difference between methanol and ethanol, the difference between ethanol and propanol is by a CH2 group.

Similarly the homologous series of alkanes:CH4, C2H6, C3H8, C4H10......

The system of assigning a name to a compound is known as nomenclature. There are two systems for

naming organic compounds

Common or trivial system  IUPAC system

The trivial names are given on the basis of the source and certain properties of organic compounds.Ex: Citric acid is named, as it is found in citrus fruits.

In the year 1947 the IUPAC that is the International Union of Pure and Applied Chemistry system of naming compounds was first developed.

The IUPAC system is a systematic nomenclature in which the name of a compound correlates to its molecular structure.

The IUPAC nomenclature system is a set of logical rules devised and used to write a unique name for every distinct compound. According to the IUPAC system of nomenclature, the name of an organic compound consists of a root word, a suffix and a prefix.

Root Word:The root word indicates the number of carbon atoms in the basic skeleton.

  Number of carbon atoms   Root word

   C    Meth

   C-C    Eth

   C-C-C    Prop

   C-C-C-C    But

   C-C-C-C-C    Pent

   C-C-C-C-C-C    Hex

   C-C-C-C-C-C-C    Hept

   C-C-C-C-C-C-C-C    Oct

   C-C-C-C-C-C-C-C-C    Non

   C-C-C-C-C-C-C-C-C-C    Dec

Example: C-C-C-C-CRoot word in the above system is ‘Pent’ (as it contains five carbon atoms).

Suffix:A suffix designate the  functional groups that may be present in the compound. The suffix is again divided into primary and secondary.

Primary suffix:Primary suffix  indicates the degree of saturation or unsaturation in the basic skeleton and is added immediately after the root word.Primary suffix + Root word → Saturated or unsaturated carbon chain

Nomenclature of Alkanes:For saturated hydrocarbons, the primary suffix “ane” should be added.

Example: The IUPAC name of a molecule which contains single bond between carbon atoms.CH3-CH3 : Eth + ane : EthaneCH3-CH2-CH3 : Prop + ane : Propane 

Nomenclature of Alkenes:

Hydrocarbons containing double bonds are known as alkenes.  For such hydrocarbons, the primary suffix “ene” should be added to the root word. Example: The IUPAC name of a molecule which contains double bond between carbon atoms.

CH2=CH2: Eth + ene:  EtheneCH3-CH=CH2: Prop + ene:  PropeneIn writting nomeclature of alkenes according to IUPAC, it is important to mention the position of double for the molecules which contain more than three carbon atoms.Example:CH2=CH-CH2-CH3:Root word: ButPrefix: 1-eneRoot word + prefix: 1-Butene

CH3-CH=CH-CH3:Root word: But Prefix: 2-eneRoot word + prefix: 2-Butene

Nomenclature of Alkynes:

Hydrocarbons that contain a triple bond between carbon atoms are known as alkynes and for naming such hydrocarbons the primary suffix “yne “should be added.Example: The IUPAC name of a molecule which contains triple bond between carbon atoms.CH≡CH: Eth + yne:  Ethyne

CH3-C≡CH: Prop + yne:  PropyneIn writting nomeclature of alkynes according to IUPAC, it is important to mention the position of triple bond for the molecules which contain more than three carbon atoms.Example:

CH≡C-CH2-CH2-CH3:Root word: PentPrefix: 1-yneRoot word + prefix: 1-Pentyne

CH3-C≡C-CH2-CH3:Root word: Pent Prefix: 2-yneRoot word + prefix: 2-Pentyne

Secondary Suffix:A secondary suffix indicates the functional group present in the carbon compound. Functional groups are defined as  specific atoms, group of atoms or ions which are part of a larger hydrocarbon chain and impart characteristic properties to the compounds.

Nomenclature of a molecules with functinal group:

   Organic Compound    Functional Group    Secondary Suffix to be used

   Alcohols   -OH   -ol

   Aldehydes   -CHO   -al

   Ketones   >CO   -one

  Carboxylic acid   -COOH   -oic aid

  Acid amides   -CONH2   -amide

  Acid chlorides   -COCl   -oyl chloride

  Esters   -COOR   -alkyl...oate

  Cyanides   -CN   -nitrile

  Thioalcohols   -SH   -thiol

  Amines   -NH2   -amine

Example: A molecule of ethyl alcohol contains two carbon atoms, so the root word should be “eth”.It is saturated so the primary suffix should be “ane” but as there is a functional group (alcohol) "–OH" in the molecule, remove the “e” from the name of the molecule and add the secondary suffix “ol”. Therefore, the IUPAC name of ethyl alcohol is “ethanol”.

CH3-CH2-OH : Eth + an+ol : Ethanol

Similarly:The IUPAC  name of the propanaldehyde molecule can be written as Propanal, CH3-CH2-CHO :Root word:PropPrimary suffix: anSecondary suffix: al Root word + Primary suffix + Secondary suffix: Propanal

The IUPAC name of acetone can be written as propanone. CH3-CO-CH3:Root word:Prop Primary suffix: an Secondary suffix: oneRoot word + Primary suffix + Secondary suffix: Propanone

And IUPAC name of acetic acid can be written as ethanoic acidCH3-COOH :Root word:Eth Primary suffix: an Secondary suffix: oic acidRoot word + Primary suffix + Secondary suffix: Ethanoic acid

Prefix: 

The parts of the name that precede the root word are called prefixes. For example, in the compound, cyclobutane, “cyclo” is the prefix that indicates the alicyclic nature of the compounds.

A primary prefix is used to differentiate acyclic and cyclic compounds. But the rules for using these are slightly different.

Ex: In cyclic compounds, the prefix cyclo is added before the word root.

Functional groups with halogen as the hetero atom are,

Functional group Formula Prefix to be used

Flourine -F Flouro

Chlorine -Cl Chloro

Bromine -Br Bromo

Iodine -I Iodo

Nomenclature of molecule with halogen as functinal group:IUPAC nomenclature of molecule of ethyl chloride.

CH3-CH2-ClRoot word: EthPrimary suffix: anePrefix: ChloroPrefix + Root word + primary suffix: Chloro ethane

In case molecules with more than three carbon atoms, it is important to specify the position of halogen.Example:

CH3-CH2-CH2-ClRoot word: PropPrimary suffix: ane

Prefix:: 1-ChloroPrefix + Root word + primary suffix: 1-Chloro propane

CH3-CH(Cl)-CH3

Root word: PropPrimary suffix: anePrefix: 2-ChloroPrefix + Root word + primary suffix: 2-Chloro propane

The system of assigning a name to a compound is known as nomenclature. There are two systems for

naming organic compounds

Common or trivial system  IUPAC system

The trivial names are given on the basis of the source and certain properties of organic compounds.Ex: Citric acid is named, as it is found in citrus fruits.

In the year 1947 the IUPAC that is the International Union of Pure and Applied Chemistry system of naming compounds was first developed.

The IUPAC system is a systematic nomenclature in which the name of a compound correlates to its molecular structure.

The IUPAC nomenclature system is a set of logical rules devised and used to write a unique name for every distinct compound. According to the IUPAC system of nomenclature, the name of an organic compound consists of a root word, a suffix and a prefix.

Root Word:The root word indicates the number of carbon atoms in the basic skeleton.

  Number of carbon atoms   Root word

   C    Meth

   C-C    Eth

   C-C-C    Prop

   C-C-C-C    But

   C-C-C-C-C    Pent

   C-C-C-C-C-C    Hex

   C-C-C-C-C-C-C    Hept

   C-C-C-C-C-C-C-C    Oct

   C-C-C-C-C-C-C-C-C    Non

   C-C-C-C-C-C-C-C-C-C    Dec

Example: C-C-C-C-CRoot word in the above system is ‘Pent’ (as it contains five carbon atoms).

Suffix:A suffix designate the  functional groups that may be present in the compound. The suffix is again divided into primary and secondary.

Primary suffix:Primary suffix  indicates the degree of saturation or unsaturation in the basic skeleton and is added immediately after the root word.Primary suffix + Root word → Saturated or unsaturated carbon chain

Nomenclature of Alkanes:For saturated hydrocarbons, the primary suffix “ane” should be added.Example: The IUPAC name of a molecule which contains single bond between carbon atoms.CH3-CH3 : Eth + ane : EthaneCH3-CH2-CH3 : Prop + ane : Propane 

Nomenclature of Alkenes:

Hydrocarbons containing double bonds are known as alkenes.  For such hydrocarbons, the primary suffix “ene” should be added to the root word. Example: The IUPAC name of a molecule which contains double bond between carbon atoms.

CH2=CH2: Eth + ene:  EtheneCH3-CH=CH2: Prop + ene:  PropeneIn writting nomeclature of alkenes according to IUPAC, it is important to mention the position of double for the molecules which contain more than three carbon atoms.Example:CH2=CH-CH2-CH3:Root word: ButPrefix: 1-eneRoot word + prefix: 1-Butene

CH3-CH=CH-CH3:Root word: But Prefix: 2-ene

Root word + prefix: 2-Butene

Nomenclature of Alkynes:

Hydrocarbons that contain a triple bond between carbon atoms are known as alkynes and for naming such hydrocarbons the primary suffix “yne “should be added.Example: The IUPAC name of a molecule which contains triple bond between carbon atoms.CH≡CH: Eth + yne:  Ethyne

CH3-C≡CH: Prop + yne:  PropyneIn writting nomeclature of alkynes according to IUPAC, it is important to mention the position of triple bond for the molecules which contain more than three carbon atoms.Example:

CH≡C-CH2-CH2-CH3:Root word: PentPrefix: 1-yneRoot word + prefix: 1-Pentyne

CH3-C≡C-CH2-CH3:Root word: Pent Prefix: 2-yneRoot word + prefix: 2-Pentyne

Secondary Suffix:A secondary suffix indicates the functional group present in the carbon compound. Functional groups are defined as  specific atoms, group of atoms or ions which are part of a larger hydrocarbon chain and impart characteristic properties to the compounds.

Nomenclature of a molecules with functinal group:

   Organic Compound    Functional Group    Secondary Suffix to be used

   Alcohols   -OH   -ol

   Aldehydes   -CHO   -al

   Ketones   >CO   -one

  Carboxylic acid   -COOH   -oic aid

  Acid amides   -CONH2   -amide

  Acid chlorides   -COCl   -oyl chloride

  Esters   -COOR   -alkyl...oate

  Cyanides   -CN   -nitrile

  Thioalcohols   -SH   -thiol

  Amines   -NH2   -amine

Example: A molecule of ethyl alcohol contains two carbon atoms, so the root word should be “eth”.It is saturated so the primary suffix should be “ane” but as there is a functional group (alcohol)

"–OH" in the molecule, remove the “e” from the name of the molecule and add the secondary suffix “ol”. Therefore, the IUPAC name of ethyl alcohol is “ethanol”.

CH3-CH2-OH : Eth + an+ol : Ethanol

Similarly:The IUPAC  name of the propanaldehyde molecule can be written as Propanal, CH3-CH2-CHO :Root word:PropPrimary suffix: anSecondary suffix: al Root word + Primary suffix + Secondary suffix: Propanal

The IUPAC name of acetone can be written as propanone. CH3-CO-CH3:Root word:Prop Primary suffix: an Secondary suffix: oneRoot word + Primary suffix + Secondary suffix: Propanone

And IUPAC name of acetic acid can be written as ethanoic acidCH3-COOH :Root word:Eth Primary suffix: an Secondary suffix: oic acidRoot word + Primary suffix + Secondary suffix: Ethanoic acid

Prefix: The parts of the name that precede the root word are called prefixes. For example, in the compound, cyclobutane, “cyclo” is the prefix that indicates the alicyclic nature of the compounds.

A primary prefix is used to differentiate acyclic and cyclic compounds. But the rules for using these are slightly different.

Ex: In cyclic compounds, the prefix cyclo is added before the word root.

Functional groups with halogen as the hetero atom are,

Functional group Formula Prefix to be used

Flourine -F Flouro

Chlorine -Cl Chloro

Bromine -Br Bromo

Iodine -I Iodo

Nomenclature of molecule with halogen as functinal group:IUPAC nomenclature of molecule of ethyl chloride.

CH3-CH2-ClRoot word: EthPrimary suffix: anePrefix: ChloroPrefix + Root word + primary suffix: Chloro ethane

In case molecules with more than three carbon atoms, it is important to specify the position of halogen.Example:

CH3-CH2-CH2-ClRoot word: PropPrimary suffix: anePrefix:: 1-ChloroPrefix + Root word + primary suffix: 1-Chloro propane

CH3-CH(Cl)-CH3

Root word: PropPrimary suffix: ane

Prefix: 2-ChloroPrefix + Root word + primary suffix: 2-Chloro propane

Carbon compounds undergo different types of chemical reactions.

Combustion:All carbon compounds react with oxygen to produce heat and light along with carbon dioxide and water. This reaction of carbon with oxygen is called combustion.

Carbon Compound + Oxygen → Carbon dioxide + water + heat and lightCH4 + 2O2 → CO2 + 2H2O + Heat and light. • Aliphatic compounds on combustion produce a non-sooty flame. • Aromatic compounds on combustion produce sooty flame.

Oxidation:Alcohols undergo oxidation in presence of oxidising agents like alkaline potassium permanganate or acidified potassium dichromate to form carboxylic acids. Example:Ethyl alcohol on oxidation with alkaline potassium permanganate or acidified potassium dichromate gives acetic acid. CH3-CH2-OH Alkaline KMnO 4 or Acidified K 2 Cr 2 O 7 → CH3-COOH

Addition reaction:A chemical reaction is said to be an addition reaction if two substances combine and form a third substance. In general unsaturated hydrocarbons like alkenes and alkynes prefers to undergo addition reactions. In addition reactions molecules add across double bond or triple bond. Hydrogenation reaction involves the addition of hydrogen to unsaturated hydrocarbons in presence of catalyst like nickel or platinum to form saturated hydrocarbons.Example:Addition of hydrogen to ethene

Addition of hydrogen ethyne. CH ≡ CH + 2H2 Ni or Pt → CH3-CH3

Addition of halogens to alkenes.CH2 = CH2 + X2 → CH2X - CH2X

Substitution reaction:A reaction in which an atom or group of atoms replaces another atom or group of atoms is called substitution reaction. Alkanes undergo substitution reactions. Example: Chlorination of methane in presence of sunlight gives a mixture of products like methyl chloride, methylene chloride, chloroform and carbon tetrachloride. CH4 + Cl2 Sunlight → CH3Cl + HClCH3Cl+Cl2 Sunlight → CH2Cl2 + HClCH2Cl2+Cl2 Sunlight → CHCl3+HClCHCl3+Cl2 Sunlight → CCl4+HCl

Polymerization reaction:Alkenes and alkynes at higher temperatures under polymerization to form bigger molecules called as polymers.Example:Ethene at 400 °C undergoes polymerization to form polyehene.

nCH2 = CH2 → [-CH2 -CH2 - CH2 - CH2-]n

Cracking:

At higher temperatures in absence of air higher hydrocarbons breaking into smaller hydrocarbons. This process is called cracking.

Example:

C10H22 Cracking at 600 - 700 ℃ → C6H14 + C4H8

The two important carbon compounds are Ethanol and Ethanoic acid.

Alcohol:Molecules in which hydroxy group attached to alkyl groups are the alcohols.The formula of alochols can be written by replacing hydrogen ("H") from alkanes with hydroxy group ("OH").R - H + OH → R - OHAlcohols can be named by replacing "e" from alkanes with "ol".Alkan -e + ol → Alkanol

Some of the important alcohols are:

             Name of the alcohol                  Chemical formula of alcohol

      Methanol     CH3-OH

      Ethanol     CH3-CH2-OH

      Propanol     CH3-CH2-CH2-OH

      Butanol     CH3-CH2-CH2-CH2-OH

      Pentanol     CH3-CH2-CH2-CH2-CH2-OH

Ethanol: 

Ethanol is considered as one of the important organic compound.The molecular formula of ethanol is C2H5OH. It is also called as ethyl alcohol.

Preparation of Ethanol:Ethanol can be manufactured through fermentation of molasses. The process involves slow decomposition of a complex organic compound like molasses into simpler compounds including ethanol, by means of microorganisms like yeast.

Physical Properties of ethyl alcohol:     •  It is a colourless inflammable and sweet smelling liquid     •  Is miscible with water     •  It is a good solvent that dissolves most known substances.     •  Ethanol can cause drunkenness on consumption, even in small quantities of dilute ethanol.     •  Extremely poisonous when consumed in pure form (absolute alcohol)

Chemical properties of Ethanol:It involves in different chemical reactions due to the presence of hydroxy group (-OH).

Reaction of ethanol with sodium:Ethanol readily reacts with sodium to form sodium ethoxide and hydrogen gas.2Na + 2CH3CH2OH → 2CH3CH2O–Na+ + H2         

Reaction with concentrated sulphuric acid:Ethanol on heating to a temperature of 443 K with excess concentrated sulphuric acid, gives ethene.

CH3-CH2-OH        Hot Conc. H ₂ SO ₄ →         CH2=CH2+H2O

Oxidatation:Ethanol undergoes oxidation in presence of Potassium dichromate to form intially ethanal and finally formsfurther oxidised ethanoic acid.

CH3-CH2-OH + K2Cr2O7 → CH3-CHO → CH3-COOH

Esterification:Reaction of ethanol with carboxylic acids is called esterification reaction. The product formed in this reaction is an ester along with water. Esters are sweet smelling substances which are used in making perfumes and as flavoring agents.Example:CH3-CH2-OH + CH3-COOH → CH3-COOC2H5 + H2O 

Uses of Ethanol:     •  Ethanol is used in pharmaceutical preparations like tincture of iodine, cough syrups, and tonics.     •  Ethanol is used in the manufacture of organic compounds like acetaldehyde, acetic acid and chloroform.     •  Ethanol is used as a preservative for biological specimen.

Acetic acid:The molecular formula of acetic acid is CH3COOH.5-8% solution of acetic acid in water is called vinegar. Preparation of Ethanoic acid:

Ethanoic acid is prepared by the oxidation of ethanol in the presence of oxidising agents like Alkaline KMnO4  or acidified K2Cr2O7.

CH3-CH2-OH    Alkaline   KMnO 4   or Acidified   K 2 Cr 2 O 7 →    CH3-COOH

Physical Properties of Ethanoic acid:     •  Ethanoic acid is a colourless corrosive liquid with a pungent odour.     •  The melting point of pure ethanoic acid is 17 0C.     •  Ethanoic acid freezes during the winter and is known as glacial acetic acid.     •  Miscible with water, ether and ethyl alcohol.

Chemical Properties of Ethanoic acid:Reaction with sodium carbonate:Ethanoic acid reacts with sodium carbonate to give sodium acetate ,carbon dioxide and water

                    2CH3-COOH + Na2CO3 → 2CH3COO-Na+ + CO2 + H2O

Reaction with sodium hydrogen carbonate:Ethanoic acid reacts with sodium hydrogen carbonate to give sodium acetate ,carbon dioxide and water.                    CH3-COOH + NaHCO3 → CH3COO-Na+ + CO2 + H2O

Reaction with base:Ethanoic acid reacts with bases to give salt and water.Example:Reaction of ethanoic acid with sodium hydroxide to form sodium acetate and water.                         CH3-COOH + NaOH → CH3COONa + H2O

Reaction with sodium hydrogen carbonate, sodiumhydrogen carbonate and with bases are the acidic properties of ethanoic acid.

Saponification:Esters react in the presence of an acid or a base to give back the alcohol and carboxylic acid. This is called saponification reaction. This is reverse reaction of esterification reaction.

CH3COOC2H5       Sodium Hydroxide →      CH3-COOH + CH3-CH2-OH

Reaction with active metals:Ethanoic acid reacts with active metals to form metal ethanoate and hydrogen gas.Example:                      2CH3COOH + 2Na → 2CH3COONa + H2 

                     2CH3COOH + Ca → (CH3COO)2Ca + H2

Reduction: Ethanoic acid is reduced to ethanol in presence of reducing reagnets like LiAlH4 (Lithium aluminum hydrate), NaBH4 (Sodium borohydrate).CH3COOH + LiAlH4 → CH3-OH

Uses of Ethanoic acid:     •  Preserve food items     •  Manufacture of artificial fibres     •  Ethanoic acid is used for coagulating latex to prepare rubber from it.     •  It is used as a reagent in the laboratory.     •  It is used in the preparation of perfumes.

Soaps are sodium or potassium  salts of long chain  carboxylic acids. They are using as cleansing agents to remove dirt, oil from the skin and clothes.

Generally soaps are prepared by heating animal fat or oil with alkalies like sodium hydroxide or potassium hydroxide. This is saponification reaction.Fat or Oil + Alkali → Soap + Glycerol

Glycerol is by -product formed in the saponification reaction. This is used in the preparation of cosmetics, paints and even explosives.

The Soap molecule has two ends with different properties. They are hydrophillic end and hydrophobic end.Hydrophillic end : Hydrophillic end dissolves in water.

Hydrophobic end:Hydrophobic which dissolves in hydrocarbons.

Cleaning action of soap:The cleaning action of soap is due to micelle formation and emulsion formation. Inside water a unique orientation forms clusters of molecules in which the hydrophobic tails are in the interior of the cluster and the ionic ends on the surface of cluster. This results in the formation of micelle.

Soap in the form of micelle cleans the dirt as the dirt will be collected at the centre of micelle.This property of soap makes it an emulsifier. The dirt suspended in micelles is easily rinsed away. This is known as cleaning action of soap.

Scum:In hard water soap don't give lather .Hard water contains calcium and magnesium salts, which combine with soap molecules to form insoluble precipitates known as scum.

Detergents:Detergents have almost the same properties as soaps but they are more effective in hard water. Detergents are generally ammonium or sulphonate salts of long chain carboxylic acids. The charged ends of these compounds do not form insoluble precipitates with the calcium and magnesium ions in water.