Carbon and its Compounds ||Class 10 || Science || CBSE Notes
Dear Students, Today we are going to share the Notes of Carbon and its Compound. These notes are prepared by the experienced teachers. These notes are free to all the students. These notes has been prepared according to the CCE pattern of school education based on NCERT Syllabus prescribed by the Central Board of School Education for Class X. All the important topics are covered in these notes.
Some Important Topics
F Interesting Facts about Carbon
F Carbon always formed covalent Bonds
F Carbon is Tetravalent
F Self combination/Catenation
F Occurrence of Carbon
E In free state
E In combined state
F Allotrophy
E Diamond
E Graphite
E Buckminster
fullerene
F Diamond
E Structure of diamond
E Uses of Diamond
F Graphite
E Structure of graphite
E Uses of Graphite
F Buckminster fullerene
F Organic Chemistry
F Organic compound
F Types of organic compounds
E Hydrocarbons
E Haloalkanes
E AlcohalsKetones
E Aldehydes
E Carboxylic acid
E Reason for large number of organic
compounds
F Hydrocarbon
E Saturated Hydrocarbon
E Unsaturated Hydrocarbon
F Alkenes
F Alkynes
E Structural and Electronic Formula
F Alkyl Groups
F Cyclic Hydrocarbons
F Naming of Hydrocarbons
E Single bond
E Double bond
E Triple bond
F Isomerism
F Homologous Series
E Homologous series of alkanes
E Homologous Series of alkenes
E Homologous Series of alkynes
Interesting Facts about Carbon
|
|
Name
|
Carbon
|
Symbol
|
C
|
Status
|
Non-Metal
|
Atomic
Number
|
6
|
Electronic
Configuration
|
2,
4
|
No.
of Valence electrons
|
4
|
No.
of electrons required to attain Nobel gas configuration
|
4
|
Valency
|
4 (Tetravalent)
|
Atomic
Mass
|
12
unit
|
Position
in group in M.P.T
|
14th
|
Position
in period in M.P.T
|
2nd
|
Bond
formed
|
Covalent Bond
|
Crystalline
allotrophs
|
Diamond,
Graphite, Buckminster fullerence
|
Carbon always formed covalent Bonds:-
The electronic configuration of
carbon is 2, 4 . It is clear that it should either loose 4 electrons or gain 4
electrons to achieve the inert gas electron configuration.
Since carbon atom is
very small. So, its electrons are strongly held by the nucleus. So, it is not
possible to remove 4 electrons from a carbon atom to give it the inert gas
electron arrangement. It is also not possible to add as many as 4 electrons to
a carbon atom due to energy considerations.
Since Carbon atoms can
achieve the inert gas electron arrangement only by the sharing of electrons,
therefore Carbon always form Covalent
Bonds.
Carbon is Tetravalent:
Since one carbon atom
required 4 electrons to achieve the eight- electron inert gas structure, therefore the valency of carbon is
4. That is carbon is tetravalent ( tetra
= four , valent = valency ). It is represented as
The most outstanding or unique
property of carbon its ability to combine with itself, atom to atom to form
long chain.
For example
Octane( C8H18 ) one of the constituent of petrol has a chain
of 8 carbon atoms. This property of carbon is also known as catenation.
It has tendency to
form long chains, branched chains and rings through covalent linkage. e.g.
Occurrence of Carbon:
Carbon is unreactive element and is found in free as well as
combined state.
(1) In free state:- Carbon occur in nature mainly in two forms ; diamond and
graphite. Another naturally occurring form of carbon called
Buckminsterfullerene has been discovered recently. Please note that only a
small amount of carbon occur as free element in the earth crust. Most of the
carbon occurs as free elements in the earth crust. Most of Carbon occurs in the
combined state.
(2) In combined state :- Carbon occurs in
nature in the form of compounds such as :- (1) Carbon dioxide gas
(2)
Carbonates like limestone marble and chalk
(3)Fossil fuel like Coal, Petroleum
and natural gas.
(4) Organic compounds
such as carbohydrate, fat, protein.
(5) Wood, cotton and
wool etc.
Allotrophy:-
It is the phenomena of existence of a chemical element in
two or more form called allotropes having similar chemical properties but
different physical properties which is due to the difference in their
structure. E.g. allotropes of Carbon
(1) Diamond
(2) Graphite
(3) Buckminster
fullerene
Diamond and graphite are the two
common allotropes of carbon which are known to us from centuries. Buckminster
fullerene is the new allotrope of carbon which has been discovered recently.
Diamond :- Diamond is a
colourless transparent substance have extraordinary brilliant shine
(chamak). Diamond is quite heavy and
extremely hard.It is the hardest known substance. It does not conduct
electricity.
Diamond burn on strong
heating to produce carbon dioxide. If we burn diamond in air, then only Carbon
dioxide gas is formed and nothing is
left behind. This shows that diamond is made up of carbon only.
Structure of diamond :-
A diamond crystal is a
giants molecule of carbon atoms.
The diamond crystal is
therefore made up of carbon atoms which are powerful bonded to one another by
network of covalent bonds.Due to this, the Diamond structure is very rigid. The
rigid structure of diamond make it very hard structure.
The compact and rigid
three dimensional arrangement of carbon
atoms in diamond gives it is a very density. The melting point of diamond is
also very high, being more than 3500 degree Celsius.
Diamond is also bad
conductor of electricity, because the four valence electrons of diamond used up
in forming the bonds.
Uses of Diamond:
(1) It is used for
cutting and grinding other hard materials,
and also used for drilling holes in the earth’s rocky layers.
(2) Diamond are used in cutting instrument
like glass.
Diamond dies are also used for drawing thin wires like
tungsten filament of the electric bulb.
(3) Diamond are used
for making jewellery.
(4) Sharp edged diamond
are used by eye surgeon as a tool to remove cataract from eyes with great
precision.
(5) Diamonds can also
be made artificially by subjecting pure carbon to very high pressure and
temperature.
Graphite :
Graphite is a greyish black diamond. Graphite is soft and
slippery to touch and it conducts electricity. If we burn graphite in oxygen
then only carbon dioxide gas is formed and nothing is left behind.
Structure of graphite:-
The structure of
graphite is very different from that of diamond. A graphite crystal consists of
carbon atoms layer or consists of sheet
of carbon atoms.
Each carbon atom in
graphite is joined to three other carbon atom to form flat hexagonal ring by
strong covalent bonds. Due to sheet like structure graphite is a comparatively
soft substance. Due to the presence of free electron that conduct electricity.
Uses of Graphite:
(1) Due to its
softness,powdered graphite is used as a lubricant for the fast moving parts of
the machinery.
(2) Graphite is used for
making carbon electrode or graphite electrodes in dry cell and electric arcs.
(3) Graphite is used for
making the core of our pencil lead and black paint.
Buckminster fullerene: Buckminster fullerene is an allotrope of carbon
containing clusters of 60 carbon atoms joined together to form spherical
molecules.
Buckminster fullerene
is a dark solid at room temperature.Itdiffers from other two are allotropes of
Carbon, diamond and graphite as it is very small molecule made of only 60 carbon atom.
Organic Chemistry
It is the branch of
Chemistry that deal with the study of organic compounds.
Organic compound :- The compound of carbon are known as organic compound expect
carbonate, bicarbonate , carbide and oxide.
Some example of
organic compounds:- Methane Ethane
methane ethanol ethanol etc.
Most of the carbon
compound are not conductor of electricity.
Some of organic compounds
(1) Plants
they give a sugar starch cellulose drugs vegetable oil insecticide which all
are organic compound.
(2) Animal they give us fat protein and oil.
(3) Coal Coal tar from coal gives us
organic Compound such as Benzene Nephthelene by its destructive distillation.
(4) Petroleum:- Petroleum oil give us organic compound like petrol diesel
kerosene etc.
(5) Dead remains :- Dead remains of living organisms give us organic Compounds
Types of organic compounds.
Some of the common
type of organic compound are
(a) Hydrocarbons
(b) Haloalkanes
(c) AlcohalsKetones
(d) Aldehydes
(e) Carboxylic acid
(organic acid)
Reason for large number of organic compounds
The two main reason
for large number of organic compound are(1) catenation and (2) tetravalency.
One reason for the
existence of a large number of organic compounds or carbon compound is that the
carbon atom can link with one another by mean of covalent bond to form a long
chain which is also known as catenation.
e.g.
Another reason for the
existence of large numbers of organic compounds that the valency of carbon is 4 and energy consideration
indicate that it is the loss or gain of 4 electrons is difficult.Due to the
reason carbon always form covalent bond by sharing its valency electrons with
atom of other element or with itself.
Hydrocarbon:
Compound which
contain hydrogen and contain carbon only are called hydrocarbon. Petroleum and
natural gas are the main source of hydrocarbons. For example:- Methane Ethane
propane butane pentane hexane etc.
Classification of Hydrocarbon
Saturated Hydrocarbon: Hydrocarbon in which carbon atom are connected by only
single bond is called a saturated
hydrocarbon (Alkanes)
General
Name
|
Alkanes
|
General
Formula
|
CnH2n
+ 2
|
Primary
|
―
ane
|
Example:- CH4 (Methane), C2H6
(Ethane), C3H8 (Propane)
Unsaturated Hydrocarbon: A hydrocarbon in which the two carbon atom are
connected by a double bond or a triple bond is called an unsaturated hydrocarbon. E.g. Ethane (C2H4)
and ethyne (C2H4).
Unsaturated hydrocarbon
are of two types
(1) Alkenes
(2) Alkynes
(1) Alkenes:- An unsaturated hydrocarbon in which that two carbon atoms
are connected by a double bond is known as alkenes. The general formula of
alkenes is CnH2n
where “n” is the number of carbon
atom in its one molecule structure of an alkenes Ethane is as follows:
Contain double bond (=)
Ethene (C2H4).
(2) Alkynes:- An unsaturated hydrocarbon in which the two carbon atom
are connected by a triple bond is called alkyne. The general formula of alkyne
is CnH2n-2 ,where
n is a number of carbon atoms in one molecule. Structure formula of alkyne is
as follows:-
H ➖ C ☰ C ➖ H
Ethyne contain trople bond (º)
Number
of
Carbon
Atoms
|
Word
root
|
1
|
Meth
|
2
|
Eth
|
3
|
Prop
|
4
|
But
|
5
|
Pent
|
6
|
Hex
|
7
|
Hept
|
8
|
Oct
|
9
|
Non
|
10
|
Dec
|
11
|
Undec
|
12
|
Dodec
|
Structural and Electronic Formula of Some Hydrocarbons
Ethane:-
Ethyne:
Ethene:
Point to remember:-
Ethane as CH3 ― H3C or H3C ― CH3
both are same.
Alkyl Groups:- The group formed by the removal of one hydrogen atom from
an alkane molecules is called an alkyl group. Example of alkyl group or methyl
(CH3‾) and Ethyl group ( C2H5‾) etc.
Please note that the
free line (―) shown on the carbon atom of a alkyl group means that one valency
of carbon atom is free in an alkyl group.
Cyclic Hydrocarbons
In order to the straight
chain hydrocarbons and branched chain hydrocarbons there are some other
hydrocarbons in which the carbon atoms are arranged in the form of a ring. Such
hydrocarbon are called cyclic hydrocarbon. The cyclic hydrocarbon may be
saturated or unsaturated.
(1) A Saturated Hydrocarbon
is cyclohexane. The formula of cyclohexane is C6H12
A molecule of cyclohexane
contain 6 carbon atom arranged in a hexagon ring with each carbon atom having
two hydrogen atom attached to it. The
structural formula of cyclohexane is shown in figure:
The saturated cyclic
hydrocarbons are called cycloalkanes. Cycloalkanes with having 3 carbon atom in
the ring is called cyclopropane (C3H6). The
cycloalkanes with 4 carbon atom in the ring is called Cyclobutane ( C4H8).
†
Please note that the general formula of the cycloalkanes is CnH2n , which is
same as that of alkenes.
(2) An unsaturated
cyclic hydrocarbon is benzene. The formula for benzene is C6H6.
A molecule of benzene is made up of 6 carbon atoms and 6 hydrogen atoms. Structure
formula is as shown in figure.
The unsaturated cyclic
compound like benzene are called aromatic compounds.
Naming of Hydrocarbons
Organic compounds have
two name : Common name and Official name.
The official name or systematic name
of organic compounds was given by International Union of Pure and Applied Chemistry (IUPAC) in 1958. The following number of things we keep in mind.
(1) The number of
carbon atom in a hydrocarbon is indicated by using the following steps.
One atom of carbon is
indicated by “Meth”
Two atom of carbon is
indicated by “Eth”
Three atom of carbon
is indicated by “Prop”
Four atom of carbon is
indicated by “But”
Five atom of carbon is
indicated by “Pent”
Six atom of carbon is
indicated by “Hex”
Seven atom of carbon
is indicated by “Hept”
Eight atom of carbon
is indicated by “Oct”
Nine atom of carbon is
indicated by “Non”
Ten atom of carbon is
indicated by “Dec”
(1) A saturated
hydrocarbon containing single bond
is indicated by writing the word one
after the stem.
(2) An unsaturated
hydrocarbon containing a double bond
is indicated by writing the word ene
after the stem.
(3) An unsaturated
hydrocarbon contain a triple bond
is indicated by writing the word yne after the stem.
Naming of Saturated Hydrocarbons
(1) Naming of CH4
:- The structure is given below
Since the compound
contain one carbon atom (Meth) and
single bond (saturated) hydrocarbon and indicated by ending ane.
Therefore, IUPAC name
become methane (meth + ane = Methane).
The common name of CH4
is also Methane.
(2) Naming of C2H6
:- The structure formula of C2H6 is given below
Similarly IUPAC name
of
(iii) C3H8
IUPAC name:- Propane
(iii) C3H8
Common name:- Propane
(iv) C4H10
(iv) C4H10
IUPAC name:- Butane
Common name:- n-Butane
(v) C5H12
IUPAC name:- Pentane
Common name:-
n-Pentane
IUPAC Nomenclature for
Branched Chain Saturated Hydrocarbons
We should remember the
following rules:-
(1) The longest chain
of carbon atoms in the structure of compound is found first and name as
derivative of alkanes. This is parent hydrocarbon.
(2) The alkyl group
present as side chains are considered as substituent and named separately
as methyl (CH3‾) and Ethyl
group ( C2H5‾) .
(3) The carbon atoms
of the longest carbon atom are numbered in such a way that the alkyl group get
the lowest possible number.
(4) The position of
the alkyl group is indicated by writing a number of carbon atom to which it is
attached.
(5) The IUPAC name of
the compound is obtained by writing the position and name of parent
hydrocarbon.
IUPAC name of C4 H10 :-
IUPAC name:- 2
methylpropane
Common name:- Iso
butane
IUPAC name of C5H12 :-
IUPAC name:- 2
methylbutane
Common name:- Iso
pentane
Naming of unsaturated hydrocarbon having double bond
Naming of C2H4
Common name:- Ethylene
Naming of C3H6
IUPAC name:- Propane
Common name:-
Propylene.
Naming of unsaturated hydrocarbon having Triple Bond
Naming of C2H2
IUPAC name:- Ethyne
Common name:-
Acetylene
Naming of C3H4
IUPAC name:- Propyne
Common name:- Methyl
acetylene.
Isomerism :
It is the
phenomena of existence of a chemical compound in two or more forms called
isomers having same molecular formula but different structural formula.
It should be notes
that as the number of carbon atoms in an organic compound increase, the number
of possible isomers increases rapidly.
Example:
(a) Isomers of
Butane:-
(n-butane C4H10)
(b) Similarly Isomers of pentane (C5H12)
Iso-pentane
2-methylbutane
Neopentane
2, 2-diamethylpropane
Isomers of Hexane: -
(C6H14)
Homologous Series:
A
homologous series is a group of organic compound having similar structure and
similar chemical properties in which the successive compound differ by CH2
group.
The various organic
compound of a homologous series are homologues.
Example of Homologous Series:-All the alkanes have the similar
structures with single covalent bond and show similar chemical properties. So
they can be grouped together in the form of homologous series.
The first five members
of homologous series of alkanes are given below.
(1) Methane
|
CH4
|
(2) Ethane
|
C2H6
|
(3) Propane
|
C3H8
|
(4) Butane
|
C4H10
|
(5) Pentane
|
C5H12
|
Homologous Series of
alkenes:-
(1) Ethene
|
C2H4
|
(2) Propene
|
C3H6
|
(3) Butene
|
C4H8
|
(4) Pentene
|
C5H10
|
(5) Hexene
|
C6H12
|
Homologous Series of
alkynes:-
(1) Ethyne
|
C2H2
|
(2) Propyne
|
C3H4
|
(3) Butyne
|
C4H6
|
(4) Pentyne
|
C5H8
|
(5) Hexyne
|
C6H10
|
Some Important Topics
✴ Functional Group
❇Halo Group
❇Alcohol Group
❇Aldehyde Group
❇Ketone Group
❇Carboxylic Acid Group
✴Coal and Petroleum
❇Coal formation
❇Petroleum formation
❇Substances burn with a flame or
without flame
✴Ethanol (or Ethyl Alcohol)
❇ Preparation of Ethanol
❇ Physical Property of Ethanol
❇ Chemical Property of Ethanol
✴ Combustion
✴ Oxidation
✴ Reaction with sodium metal
❇ Dehydration of Ethanol
❇ Uses of Ethanol
✴ Harmful Effect of Drinking Alcohol
❇ Denatured Alcohol
❇ Test for Alcohol
✴ Sodium Metal Test
✴ Sodium Metal Test
✴ Easter Test
✴ Ethanoic Acid or Acetic Acid
❇ Physical Property of Ethanoic Acid
❇ Chemical Property of Ethanoic Acid
✴ Action on Litmus
✴ Dilute Ethanoic
✴ Reaction with Sodium H -Carbonate
✴ Reaction of Ethanoic acid with
Alcohols
❇ Uses of Ethanoic Acid
❇ Test for Ethanoic Acid
✴ Shops
❇ Manufacture of Soap
❇ Structure of Soap
❇ Cleansing Action of Soap
❇ Limitation of Soap
✴ Detergents
Functional Group
An atom or a group of
atoms which makes a carbon compound (or Organic Compound) reactive and decides
its properties is called a functional
group.
The alcohol group –
OH, present in ethanol C2H5OH, is an example of
functional group. Some of the important functional groups are Halo group (or
Halogeno group). Alcohol group, Aldehyde group, Ketone group, Carboxylic Acid
group, Alkene group and Alkyne group. These are discussed below:
1. Halo Group :ªX (X can ve Cl, Br or I)
The halo group can be
chloro- Cl, bromo – Br, or iodo- I , depending upon whether a chlorine, bromine
or iodine atom is linked to a carbon atom of the organic compound.
Chloro group is
present in Chloromethane CH3 ― Cl,
Bromo group is present
in bromomethane CH3 ― Br
And Iodo group is
present in Iodomethane CH3 ― I
The haloalkanes can be
written as (R ― X ) where R is an alkyl group and X is the halogen atom.
(2) Alcohol Group:-
OH
The alcohol group is made up of one oxygen atom and one
hydrogen atom joined together. The alcohol group is also known as alcoholic group
or hydroxyl group. The compound containing alcohol group are known as alcohols.
Example of compound containing alcohols group are : methanol CH3OH,
ethanol C2H5OH.
The general formula can be written as R―OH where R is alkyl
group and OH is the alcohol group.
Aldehyde Group:-
The aldehyde group consists of one carbon atom, one hydrogen atom and one oxygen atom joined together.
The aldehyde group consists of one carbon atom, one hydrogen atom and one oxygen atom joined together.
or we can say that these are the organic compound which
contain ―CHO group (i.e. aldeyde group as a functional group) attached to a
c―atom of an alkane molecule.
Ketone Group :
Some example are :- CH3COCH3
(Propanone), CH3COCH2CH3 (Butanone)
A Ketone group is always between two alkyl group. It can
never be at the end of a carbon chain because it has two valency which have to
be satisfied by two alkyl groups.
Carboxylic Acid Group:
These are the organic compound which contains ― COOH group as a functional group attached
to a c―atom group as a functional group attached to a c―atom of alkane.
For example:- methanoic acid H―COOH and ethanoic acid CH3―COOH.
Coal and Petroleum
When a fuel is burned, the energy is released mainly as heat
and some light, Most of the fuel which we can used today are obtained from coal,
petroleum and natural gas.
Coal is complex mixture of compounds of carbon, hydrogen and
oxygen and some free carbon. Small amounts of Nitrogen and sulphur compounds are
also present in coal.
How Coal was formed
Coal was formed by the decomposition of large plants and trees
buried under the trees million years ago. It is believed that millions of year
ago, due to earthquakes and volcanoes etc, the forests were buried under the
surface of the earth and got covered with sand, clay and water. Due to high
temperature and high pressure inside the earth, and in the absence of air would
was converted into coal.
How petroleum was
formed :- Petroleum
oil were formed by the decomposition of remains of extremely small plants and
animals buried under the sea millions of
years ago.
Why do substances burn with a flame
or without flame
(1) When the oxygen supply is sufficient then the fuel burn
completely producing a blue flame. In a gas stove or cooking gas there is sufficient
oxygen so produce much heat but less light. Therefore, it is said to be in non-luminous
(or non light giving) flame.
(2) When the oxygen supply is insufficient then the fuels
burns incompletely producing mainly a yellow flame. The yellow flame producing
light so it is said to be luminous flame.
Ethanol (or Ethyl
Alcohol)
Preparation of Ethanol:- Ethanol is commercially prepared by
the fermentation of sugar present in the molasses by the action of enzyme
called invertase and zymase secreated by yeast at a control temperature of 200
C ― 300 C
It consists of following two reaction:-
(i) 
(ii) 
The vessel used for fermentation is design in such a way that
it allows CO2 to escape out of it, but does not allow the fresh air to
enter into the vessel as it can oxidised Ethanol
to Ethanoic acid.
Physical Property of Ethanol:-
(a) It is a colorless
liquid with pleasent smell.
(b) Its boiling point
is 780 C.
(c) It is lighter than
water.
(d) It is soluble in
water.
(e) It remains as
liquid even in winter.
(f) It is neutral.
(g) It is covalent
compound.
(h) It is a poor
conductor of electricity.
(i) It catches fire
easily.
Chemical Property of
Ethanol:
(a) Combustion:- Ethanol
burns in air to produce CO2 water vapours and lot of heat as
(b) Oxidation:-
When ethanol is heated with alkaline potassium permanganate solution (or
acidified potassium dichromate) it gets oxidized to ethanoic acid.
(c) Reaction with
sodium metal :- Ethanol react with sodium to form sodium ethoxide and
hydrogen gas.
Reaction with Carboxylic acids or with ethanoic acid :-
Ethanol reacts with ethanoic acid in the presence of concentrated H2SO4
to produce a sweet smelling ester as ethyl ethanoate:
Dehydration of Ethanol:- When ethanol is heated with excess
of conc Sulphuric acid at 1700 C , it get dehydrated to form ethane.
Uses of Ethanol
(1) Ethanol is used in the manufacture of paints, varnishes,
liquiors, medicines, perfumes, dyes, soap
and synthetic rubber.
(2) Ethanol alcohol is used as a solvent. Many organic
compounds which are insoluble in water are insoluble in water are soluble in
ethyl alcohol.
(3) Being a good solvent, it is used in medicine such as as
tincture iodine, cough syrups and many tonics.
(4) Ethyl alcohol is used as a fuel in cars along with petrol.
it is used as a fuel in spirit lamps.
(5) It is used in alcoholic drinks like whisky, wine beer and
other liquors.
(6) It is used as an antiscptic to sterilize wounds and
syringes in hospital and dispensaries.
Harmful Effect of
Drinking Alcohol
(1) Alcohol slows down the activity of nervous system and the
brain due to be the judgment of a person is impaired and his reaction become
slow. So a person driving a car under the influence of alcohol cannot judge a
situation properly and act quickly in case of an emergency.
(2) Alcohol drinking inhabitation (mental restrain) due to
which a drunken man become quarrelsome. This leads to quarrels and fights which
increase violence and crime in society.
(3) Drinking alcohol heavily land of straggered movement,
slurred speech, blurred vision and vomiting.
(4) Heavy drinking of alcohol over a long time may damage the
stomach, liver, heart and even brain.
(5) Heavy and continuous drinking of alcohol makes the person
bankrupt.
(6) The drinking of adulterated alcohol contain methyl
alcohol (methanol) cause serve poisoning leading to brightness and even death.
Denatured Alcohol :- To prevent the misuse of
industrial alcohol for drinking purposes (or black marketing) ethyl alcohol meant
for industries is denatured by adding some amount of poisonous substance like methanol
, pyridine or copper sulphate, etc. So denatured alcohol is ethyl alcohol which
has been made unfit for drinking purpose by adding small amount of poisonous
substance like methanol.
Test for Alcohol
(1) Sodium Metal
Test:- If on adding sodium metal to the organic liquid, the bubble of
hydrogen gas are produce then it indicate that the given organic liquid is
ethanol.
(2) Easter Test:-
If on warming solution with some glacial ethanoic acid and a few drop of cons
sulphuric acid a sweet smell produced that is ester produce, it indicate that
solution is ethanol.
Ethanoic Acid or Acetic
Acid
Ethanoic acid can be prepared by the oxidation of Ethanol
which can be done either by alkaline KMnO4 or acidic K2Cr2O7
A dilute solution of ethanoic acid in water is called vinegar. It contain 5 to 8% acetic acid.
Physical Property of Ethanoic Acid:
(a) It is a colorless liquid having a sour taste
and a pungent smell.
(b) Its boiling point is 1180 C.
(c) Pure ethanoic acid
is called glacial ethanoic acid (or glacial acetic acid).
(d) It miscible with
water in all propotions.
(e) It is a good
conductor of electricity.
Chemical Property of Ethanoic Acid
(a) Action on Litmus:- Ethanoic acid turn blue Litmus to Red
as it produce H+ (aqions)
in the solution.
(b) Dilute Ethanoic acid turn indicator paper to Orange showing
that pH is about 4 which tell us that
it is a weak acid.
(c) Reaction with
Sodium H -Carbonate
Ethanoic acid react with sodium hydrogen-carbonate to evolve
brisk effervescence of carbon dioxide gas:
This reaction is used as a test of ethanoic acid.
Reaction of Ethanoic
acid with Alcohols:-
It reacts with alcohols in the presence of little of
concentrated Sulphuric acid to form Easter.
Example: Easter are usually volatile liquids having sweet
smell or pleasant smell.
Uses of Ethanoic Acid:
(1) Dilute ethanoic
acid in the form of vinegar is used as a food preservative in the preparation
of pickles and sauces.
(2) Ethanoic acid is
used in the manufacture of acetone as ester used in perfumes.
(3) It is used for
making cellulose acetate which is an important artificial fibre.
(4) It is used in
preparation of dyes, plastics and pharmaceuticals.
(5) It is also used to
coagulate rubber from latex.
Test for Ethanoic Acid:
If a pinch of sodium bicarbonate is added to ethanoic acid,
the evolution of CO2 gas with brisk effervescence show that the
given organic compound is carboxylic acid.
Shops
A soap is the sodium or potassium salt of long chain
carboxylic acid (fatty acid) which has cleansing property in water. Example of
soaps are:- Sodium Stearate and Sodium palmitate.
Manufacture of Soap:- Soap is made by heating animal fat
or vegetable oil with concentrated sodium hydroxide solution (caustic soda
solution)
General reaction:
General reaction:
Example:-
The process of making shop by hydrolysis of fats and oil with
alkalis is called saponification. The saponification gets completed soap is obtained
in the form of solution. Common salt is then added to precipitate out all the
soap from the aqueous solution. It decrease the solubility of due to which all
the soap separate out from the solution in the form of liquid.
Structure of Soap:
A soap molecules is made up of two parts: a long hydrocarbon
part and a short ionic part containing ― Coo‾
Na+ group.
When Soap is dissolved in water it forms a colloidal
suspension in water in which the soap molecules cluster together to form
spherical misclles as in figure.
Micelle formation takes place when soap is added to water
because the hydrocarbon chain of soap molecules (water repelling) which are insoluble
in water but the ionic end of soap molecules are hydrophilic (water attracting)
and hence soluble in water.
When the dirt cloth is agitated in soap solution, the oily
and greasy particle present on its surface and entrapped by soap micelles get
dispersed in water due to which the soap water become dirty but the cloth get
clean.
Limitation of Soap
Following are the limitation of soap:-
(1) Soap is not suitable for washing clothes with hard water,
it is because soap reacts with calcium and magnesium salts to form insoluble
precipitate called scum which cloth a dirty appearance.
Detergents:
Detergents are also called soap less soaps because though
they act like a soap in having cleansing properties they do not contain the
usual soaps like sodium stearate etc.
Detergent are better cleansing agents than the soap because
they can be used for washing even in hard water.
A detergent in the sodium salt of long chain benzene sulphonic
acid (or the sodium salt of long chain alkyl hydrogen sulphate) which as
cleansing properties in water.
Soap
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Detergent
|
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1
|
It is the sodium salt of long chain carboxylic or
fatty acid which has cleansing action in water.
|
It is the sodium salt of long chain.
(a) Benzene Sulphonic acid.
(b) alkyl hydrogen sulphate which has cleansing
action in water.
|
2
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Example: Sodium Stearete C17H35‾
Coo―Na+
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Example: Sodium-n-dedecyl benzene sulphonate.
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3
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They are obtained from animal fats and vegetable
oils.
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They are obtained from petroleum products.
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4
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They are biodegradable and hence does not cause
pollution.
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They are biodegradable and hence cause pollution
|
5
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They have relatively weaker cleansing action.
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They have a stronger cleansing action.
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6
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They do not work well in hard water.
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They work well in hard water.
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7
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They form scum in hard water
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They do not form scum in hard water.
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8
|
The short ionic part is Coo―Na+
(hydrophilic).
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The short ionic part is So‾3 Na+ or SO4 Na+.
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