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A Complete Educational Website for FREE : CHEMISTRY COMPLETE MATERIAL PART 1


Matter : Anything which occupies space has mass & can perceived by our physical senses is called Matter.
    There are three states of matter solids, liquids and gaseous.

    Solids    Liquids    Gases      
1.    They have definite shape and definite volume.    They have no definite shape, but have a definite volume.    They have neither definite shape nor definite volume.      
2.    Position of the molecules of solid is fixed.    Position of molecules of a liquid is not fixid.  The molecules can change their position within the    Position of molecules of a gas is not fixed.  The molecules can move freely in all direction      
3.    Solids cannot be compressed    Liquids can be very slightly compressed    Gas can be easily compressed      
4.    Solids cannot flow. They can be heaped.    Liquids flow from higher to lower level    Gases can flow in all directions      
5.    Solids have very strong intermolecular spacs.    Liquid have small intermolecular spaces, which is    Gases have very large intermolecular space.      
6.    Solids have very strong intermolecular forces of attraction    Liquids have less intermolecular force of attraction than the solids.    Gases have negligle intermolecular forces of attraction.      
7.    Solids have infinite number of free surfaces.    Liquids have only one free surface    Gases have no free surface      
8.    Solids do not need a vessel to contain them    Liquids need a vessel to contain them    Gases need a vessel to contain them   

 Pure substances                 Mixtures

Elements     Compounds    Homogenious   Heterogenious

Metals   Non-metals      Metalloids     Nobel gases
Pure substances : A homogeneous material which contains particles of only one kind and has a definite set of properties is called pure substances.
Element : A pure substance which con not be broken into two or more simpler substances by any known physical or chemical method is called element.
An element is made of only one kind of atoms.
Metals.      2. Non-metals     3. Metalloids.    
4. Noble gases

Metals :
An element is a metal, if it has the following characteristics.
It has a luster, i.e., it has a metallic glow.
It is a good conductor of heat and electricity.
It is ductile, i.e., it can be drawn into wires.
It is malleable, i.e., it can be beaten into sheets.
It is solid at room temperature.
It has a high melting point and high boiling point.
It produces a sonorous sound on being hit.
Examples of some metallic element are sodium, potassium, iron, copper, silver, gold, platinum, magnesium, nickel, aluminium.
Non-metals :
An element is a non-metal, if it has the following characteristics.
It has no luster, i.e., it cannot be polished.
It is a bad conductor of heat and electricity.
It is not ductile, i.e., it cannot be drawn into wires.
It is not malleable, i.e., it cannot be beaten into sheets.
It is a gas or a brittle solid at room temperature.
It has low melting point and low boiling point.
It does not produce a sonorous sound on being hit.
Examples of some non-metallic elements are hydrogen, carbon, nitrogen, oxygen, iodine, chlorine, bromine, fluorine, phosphorus.
Metalloids : Elements which exhibit some properties of metals and some properties of non-metals are called metalloids.
Examples of some metalloids element are boron, silicon, germanium, arsenic, antimony, tellurium and polonium.
Noble gases : these elements are found in ir in the form of gas in very small amounts, therefore, some times are called rare gases.  They are called noble gases, because they do not react chemically with any known element.
Noble gases are Helium, Neon, Argon, Krypton, Xenon and Radon.
Compound : A compound is a pure substance which is composed of two or more elements combined chemically in a fixed proportion by weight and cab be broken into smaller parts of elements by chemical method only.
Mixture : If two or more substances (elements or compounds or both) mixed together in any proportion do not undergo any chemical change but retain their characteristic the resulting mass is called mixture.
Mixtrure’ are two types:
Heterogenious mixture.
Homogenious mixture.
Heterogenous mixture : A mixture in which various constituents are not mixed uniformly is called heterogeneous mixtrure.
Eg: Sand, Salt and sulphur
Homogenious mixture : A mixture in which different constituents are mixed uniformly is called homogenious mixture.
Eg : all alloys : Brass
Commonly used separating Techniques for Mixtures
S.No.    Types of mixture    Methods of separation      
1.    Solid-solid (Heterogeneous)
Eg: Salt with sugar, Gun powder    Hand-picking, winnowing, sieving, magnetic separation, sublimation      
2.    Solid-liquid (Heterogeneous)
Eg: Muddy water    Decantation, loading, filtration, centrifugation      
3.     Solid-liquid (heterogeneous)
Eg: Salt and sugar solution with water    Evaporation, distillation      
4.    Liquid-liquid (Heterogeneous)
Eg: Water with kerosene    Decantation, using a separation funnel      
5.    Liquid-liquid(Homogeneous)
Eg: Water with alcohol    Distillation   
Separation method

S.N    Technique of separation    Type of mixture    Method of separation    Separation of       
1.    Hand-picking    Solid-solid    Byhad picking particle of different sizes & colours    Pebbles from pulses      
2.    Sieving    Solid-solid    By sieving large sized particles from smaller ones    Bran from wheat flour      
3.    Winnowing    Solid-solid    By separating lighter particles from heavier particles by allowing them to fall from  height    Husk form wheat      
4.    Magnetic    Solid-solid    By picking out the magnetic particles from the non-magnetic using a magnet    Iron from plastic      
5.    Sublimation    Solid-solid    By heating the mixture where the sublimable sold turns into vapour and solidifies on cooling    Ammonium chloride from sodium chloride      
6.    Sedimentation & Decantation    Insoluble solid-liquid    By setting down under gravity the solid particle & decanting out the liquid.    Sand from water      
7.     Centrifugation    Insoluble sold-liquid    By setting down under mechanical rotation the solid particles of a mixture    Milk from cream. Blood cells from blood      
8.    Filtration    Insoluble solid-liquid    By filtering out the insoluble solid using a filter paper or strainer.    Chalf from water. Tea leaves from tea.  Clay from watdr      
9.    Evaporation    Soluble
solid-liquid    By evaporating the liquid in the mixture leaving behind the solid component    Salt from sea water. Sugar from sugar solution      
10.    Distillation    Soluble
solid-liquid    By distilling i.e. evaporation followed by condensation of the liquid component the solid remains behind    Salt from sea water.  Impurities from water      
11.    Separating funnel    Liquid-liquid    By settling down of the heavier immiscible liquid from the lighter one    Kerosene oil from water.  Oil from water   
Atomic structure
According to Dalton’s theory atom is indivisible.

    Electron    Proton    Neutron      
Discovered     J.J.Thomson (1896)    Goldstain (1886)    James Chadwick(1932)      
Charge    -1.6 x 10-19 C    1.6 x 10-19 C    0      
Mass    9.1 x 10-31Kg    1.672 x 10-27 Kg    1.6725 x 10-27      
Charge in ESU    -4.802 x 10-10 esu    4.802 x 10-10 esu    0   
Cathode rays is a stesam of flow of electrons from cathode to anode i.e electrons
Anode rays move from anode to cathode - Proton
e/m ratio of electron was given by J. J. Thomson
In the atom both proton and Neutrons are present in the nucleous, electrons are revolving around the nucleus in particular orbits.
Bothe proton and neutrons present in the necleus are called Nucleons. 
Number of electrons present inany orbit  is 2n2
Rutherford proposed a model of the atom called Nuclear model of atom.
Atomic number (Z) : Number of protons in the nucleus of an atom or ion.
  Number of electrons in a neutral atom.
Mass Number (A) : Number of protons (Z) + Number of Neutrons.
Number of neutrons (n) is equal to A – Z
Eg:     11Na23 Number of neutrons in Sodium
        n = A – Z        11 – Protons
           = 23-11        11 – Electons
            = 12
Isotopes : The atoms of the same element which have the same atomic number but different mass number are called isotoes.
Eg :     (a) 1H1, 1H2, 1H3        (b) 92U235 and 92U238
Isobars : The atoms of different elements which have same mass number but different atomic numbers are called isobars.
Eg:    (a)  and         (b)    and
Isotones : Different elements which have the same number of neutrons.
Eg: 11Na23  and 12Mg24 (12 =12)
Quantum Numbers:
Principal Quntum number (n) by Niels Bohr
Azimuthal Quantum number (l) by Sommer feld
Magnetic Quantum number (m) by Lande
Sin Quantum number (s) by Goudsmit cuhlen beck
n :- tells about energy, radius number of electron in main
     energy shell.
l :- Shape (sub shells)           m :- Orentation
s :- Direction of electons
Order : 1s < 2s < 2p < 3s < 3p < 4p < 3d < 4p < 5s < 4d < 5p < 6s < 4f < 5d < 6p
Sub Shell : s – 2, d – 10, p – 6, f  - 14 

No    Element    Syl    Electronic Configuration    K    L    M    N      
1    Hydrogen    H    1s1    1                  
2    Helium    He    1s2    2                  
3    Lithium    Li    1s2 2s1    2    1              
4    Beryllium    Be    1s2 2s2    2    2              
5    Boron    B    1s2 2s2 2p1    2    3              
6    Carbon    C    1s2 2s2 2p2    2    4              
7    Nitrogen    N    1s2 2s2 2p3    2    5              
8    Oxygen    O    1s2 2s2 2p4    2    6              
9    Fluorine    F    1s2 2s2 2p5    2    7              
10    Neon    Ne    1s2 2s2 2p6    2    8              
11    Sodium    Na    1s2 2s2 2p6 3s1    2    8    1          
12    Magnesium    Mg    1s2 2s2 2p6 3s2    2    8    2          
13    Aluminium    Al    1s2 2s2 2p6 3s2 3p1    2    8    3          
14    Silicon    Si    1s2 2s2 2p6 3s2 3p2    2    8    4          
15    Phosphorus    P    1s2 2s2 2p6 3s2 3p3    2    8    5          
16    Sulphur    S    1s2 2s2 2p6 3s2 3p4    2    8    6          
17    Chlorine    Cl    1s2 2s2 2p6 3s2 3p5    2    8    7          
18    Argon    Ar    1s2 2s2 2p6 3s2 3p6    2    8    8          
19    Potassium    K    1s2 2s2 2p6 3s2 3p6 4s1    2    8    8    1      
20    Calcium    Ca    1s2 2s2 2p6 3s2 3p6 4s2    2    8    8    2   
The maximum no of electrons present in any orbitals – 2
Valency : The valency is the combining capacity of an element.
(IA) Alkalimatals : H, Li, Na, K, Rb, Cs, Fr – Valency is ‘1’
(IIA) Alkali earth metals : Be, Mg, Ca, Sr, BA, Ra – Valency is ‘2’
III(A) : B, Al, Ga, In, Tl – Valency is ‘3’
IV (A) : C, Si, Ge, Sn, Pb – Valency is ‘4’
Upto I(A) to IV(A) Valency = Valency electrons
From V(A) to VIII Valency ≠ Valency electrons
    Valency = a – 8            a = Valency electrons                   
  For O – Valency  = -2   F, Cl, Br, I – Valency = -2
Composition of earth crust: Earth crust is the source of many elements. Oxygen is most abundant element present in earth crust.  Among metals aluminium is present in most abundance in earth crust and iron comes second.  The percentage of different element in earth crust is :

Element    Oxygen    Silicon    Aluminum    Iron    Calcium      
Percentage    49    26    7.5    4.2    3.2      
Element    Sodium    Potassium    Magnesium    Hydrogen    Other      
Percentage    2.4    2.3    2.3    1    2   

Depends upon the nature of the metals.  Metals occur in nature in tow forms.
Native Ores: These ores contain metal in free state.  For example : Silver, Gold, Platinum, Mercury, Copper, etc. 
In combined state : Reactive metals are found in combined state in nature.  Such meals are attacked by O2, H3O, CO2 etc., Na, Mg, Ca, Fe, Cu, Zn, Al, Pb, etc., occur in combined state in nature.  These metals are not found in free state.
Ores of Metals
Aluminum (Al)    -    Bauxite
Magnesium (Mg)    -    Dolomite (CaCO3, MgCO3)
Lead (Pb)        -    Galena (PbS)
Mercury (Hg)    -    Cinnabar (HgS)
Iron (Fe)        -    Haematite (Fe2O3)
Copper (Cu)        -    Malachite (CuCO3, Cu(OH)2)
Gold (Au)        -    Bismuthaurite
Metallurgical processes:  The process of extraction of metal from its ores is called metallurgy.  Metallurgy involves the following five steps:
Concentration (Dressing)
Concentration (Dressing) : Ore obtained from mines often contain non-metallic and rocky materials such as sand, clay, silicates, etc.,  These impurities are called gangue or matrix.  The process of removing the gangue and thereby increasing the concentration of the metal in the ore is called concentration of the ore.  Ores may be concentrated by several methods which depend upon the nature of the ore and the impurities present in it.  Following are the important methods of concentration.
Gravity separation: The ore is powdered.  It is then washed in running stream of water.  The lighter earthy materials and gangue are washed away while the heavy ore particles remain behind.  The oxide ore of iron Fe2O3 and Fe3O4 are concentrated by this method.  This method is also called lavigation.
Froth floatation process : Sulphide ores are generally concentrated by this method.
Principle: This process is based on the preferential wetting the ore particles and gangue by a liquid.
Method: The ore is powdered and is then placed in a water tank.  Now some pine oil and potassium ethlxanthate is added in it.  A strong stream of air is passed in the tank containing water and powdered ore.  The whole mass is agitated and froth is formed.  Ore particles are preferentially wetted by the oil and come at the surface along with the froth.  The impurities are wetted by water and remain behind in the tank.  The ore particles are separated from the froth.
Magnetic Separation :
Principle: This process is based upon magnetic properties of the ore and gangue.  If the ore or the impurity present is magnetic substance from the non-magnetic substance.
Method : Ore is concentrated by a magnetic separator.  It  consists of a leather belt moving over two rollers.  One of the rollers is magnetic.  The powdered ore is put on the belt.  The magnetic portion of the ore falls nearer to the magnetic roller.  The non-magnetic portion falls further off the magnetic roller.
This method is used to concentrate tin stone (SnO2).  It contains magnetic oxide ion (Fe3O4) as impurity.  The magnetic impurity of Fe3O4 is collected near the magnetic roller while the ore particles of SnO2 fall further off the magnetic roller.
Calcination : The concentrated or is heated in absence of air below its melting point.  This process is called calcinations.  On calcinations metal carbonates and metal hydroxides are decomposed to give metal oxides.  Moisture, water of  hydration and other volatile impurities present in the ore are removed.  On calcinations, the ore becomes porous.  Thus ore is heated uniformly.
Roasting : The concentrated ore is heated alone or mixed with some other substance below its melting point in the presence of air.  The ore and impurities get oxidized.
Smelting :  In this process the roasted ore is mixed with coke and a suitable flux and is then heated in the presence of air at high temperature.
Purification of metals : Several methods are used to purify metals.  The method used depends upon the nature of the metal and the impurity present in it.
Electrolytic process : Co[[er, Silver, Gold, Lead, etc. are purified by this method.  It is an important method for the purification of metals.  Pure metal is made cathode and impure metal anode.
Liquation method : Pb, Sn, Bi, etc., metals are purified by this method.  This method is used to purify those metals which have low melting point and the impurity present has high melting point.  Impure metal is heated on an inclined hearth.  Metal melts and flows down.  Impurities remain behind.
Distillation method : Cd, Zn, Hg, etc., metals are purified by this method.  This method is used to purify those metals which are volatile.  The metal is heated and the vapours formed are condensed.  Mercury is purified by distilling it under reduced pressure.
Poling : This method is applied for the metals which contain impurity of their own oxides.  For example Cu2O in blister copper, SnO2 in impure tin.  In this method green wooden poles are used to stir the molten crude metal sample.  So that organic matter in the poles acts as  reducing agent and reduces the oxide impurities.
Cupellation : This process is applied when crude metal contain impurities of other metal which form volatile oxides.  Impurities are oxidized to volatile products and removed.  For example, the impurityof lead from silver is removed by this method.
ALLOYS: An alloy is a homogeneous mixture of two or more metals or a metal and a non-metal. Example: Bronze is an alloy of copper and tin,
Properties of Alloys:
Alloys form a homogenous mixture
Alloys are more resistant to corrosion
They are harder and stronger than constituents.
They are less malleable and less ductile than constituents.
They may have higher or lower melting points than that of constituents.
Hey have improved properties than that of constituents.
They have lover electrical conductivity than pure metals
Brass             –     Cu + Zn
Bronze         –     Cu + Sn
German Silver     –     Cu + Zn + Ni
Gun metal         –     Cu + Sn + Zn
Stainless steel     –     Fe + Cr+ Mn + C
Bell metal        -    Cu + Sn
Steel            -    Fe + C
Transformation of substances
Types of chemical changes :
Physical change
Chemical change
Physical chance : Those changes in which only physical properties of the substance change are called physical change. They may be change in colour, physical state, shape and size.

After the physical change has occurred the substances can be easily converted back by reversing physical conditions physical changes are temporary and reversible change.
                     Solid ⇌ Liquid ⇌Gas


              Gas                                       Solid

Chemical changes : Those changes in which new substances are formed are called chemical changes.  It is permanent and irreversible.
Examples of chemical changes :
Cooking of food
Burning of candle
Rusting of iron etc.,
Example of both physical & chemical changes :
Burning of wax
Sublimation of Nh4Cl
Action of heat on Zinc hydroxide
Action of heat on sodium nitrate

Types of chemical changes :
Chemical combination
Chemical decomposition
Chemical displacement
Chemical double decomposition
Chemical combination : It is the combination of two or more substance and form new substance. it is exothermic.
C + O2 → CO2↑   b. N2 + O2 → 2NO↑
Chemical decomposition : Substance split into  two or more simpler substances.
CaCO3 → CaO + CO2   b. 2PbO2 → 2PbO + O2↑
Chemical displacement : Chemical displacement is a chemical reaction in which an atom displaces another atom from a compound.
A + B – C → A – B + C
Mg + 2HCl → MgCl2 + H2
More reactive metal can displace less reactive metals.
Chemical double decomposition : Chemical double decomposition is a chemical reaction in which there is an exchange of radicals between two ionic compounds.
Na2SO4 + BaCl2 → 2NaCl + BaSO4↓
Preparation of (H2)


Common Name    Chemical Name    Formula      
Blue Vitiol    Copper Sulphate    CuSO4. 5H2O      
Green Vitriol    Ferrous Sulphate    FeSO4. 7H2O      
Epsom    Magnesium Sulphate    MgSO4. 7H2O      
Plaster of Paris    Calcium Sulphate    CaSO4. ½ H2O      
Gypsum    Calcium Sulphate    CaSO4. 2H2O      
Washing Soda    Sodium Carbonate    Na2CO3.10H2O      
Common Solt or Rock Salt    Sodium Chloride    NaCl      
Nitre or Saltpetre    Potassium nitrate    KNO3      
Baking Soda    Sodium bicarbonate    NaHCO3      
Chalk    Calcium Carbonate    CaCO3      
Caustic lunar    Silver nitrate    AgNO3      
Quick lime    Calcium Oxide    CaO      
Slaked lime or Milk of lime    Calcium hydroxide    Ca(OH)2      
Alum    Potassium aluminium Sulphate    K2SO4Al2(SO4)3 . 24H2O      
Bleaching Powder    Calcium oxychloride
Calcium chlorohypochlorite   
Hypo    Sodium thiosulphate    Na2S2O3. 5H2O      
Caustic Soda    Sodium hydroxide    NaOH      
White Vitriol    Zinc Sulphate    ZnSO4. 7H2O      
Tear gas    Chloropicrin    CCl3NO2      
Dry Ice    Solid Carbondioxide    CO2      
Marsh gas    Methane    CH4      
Laughig gas    Nitrousoxide    N2O      
Red lead    Lead tetroxide    Pb3O4      
Grain alcohol (Spirit)    Ethyl alcohol    C2H5 OH (or)
Marbles    Calcium carbonate    CaCO3      
Picric acide    2,4, 6 – Trinitrophenol    C6H2(OH)(NO2)3          
Chloroform    Tri-Chloromethane    CHCl3      
Aspirin    Acetyl salicylic acid    C9H8O4      
T.N.T    Tri-nitrotoluence    C6H5(NO2)3      
Water    Hydrogen mono Oxide    H2O      
Glucose    Dextrose    C6H12O6      
Carborundum    Silicon carbide    Sic      
Heavy water    Duteriumoxide    D2O      
Oil of vitriol    Sulphuric acid    H2SO4      
Muratic acid    Hydrocloric acid    HCl      
Chilesaltpetre    Sodiumnitrate    NaNO3   

Cryolite            -    Na3AlF6
Bauxite            -    Al2O3.2H2O
Acetic acid (or) Venigar    -    CH3COOH or C2H4O2
Acid                -    CH3COOH or  - COOH
Aldehyde            -    CH3CHO or H>C=O
Ketone            -    CH3CO-CH3 or >C=O
Urea                -    NH2CO NH2
Producer gas        -    CO + N2 + H2
Water gas            -    CO + H2
Ozone            -    O3
Heavy hydrogen        -    D2
Calsium chloride        -    CaCl2
Carbon monoxide        -    CO
Carbon dioxide        -    CO2
Ammonia            -    NH3
Ferric Oxide            -    Fe2O3
Ammonium bisulphate    -    NH4HSO4
Megnesium phosphate    -    Mg3(PO4)2
Sodium phosphate    -    Na3PO4
Megnesium chloride    -    MgCl2
Calcium sulphate        -    CaSO4
Calcium bicarbonate    -    Ca(HCO3)2
Megnesium bicarbonate -    Mg(HCO3)2

Mendeleeff’s periodic law’s are depends upon periodic function of their atomic weight.

Contributor    Classification    description      
Johann Dobereiner    Law of triads    Developed ‘triads’ groups of three elements with similar properties.
Eg.,Lithium, sodium and potassium;
calcium, strontium and barium;
chlorine, bromine and iodine      
John newlands    Law of Octava    The known elementws were arrenged in order of atomic weights (> 60) and observed similarities between the first and eight element (upto calcium)      
Lothar Meyer    Lothar Meyer’s arrangement    Compiled a periodic table of 56 elements, based on the periodicity of properties such as molar volume, when arranged in order of atomic weights.      
Dmitri medeleev    Mendeleev’s Periodic Law    Pysical and chmical properties of the elements are a periodic function of their atomic masses.      
Henry Moseley    Modern Periodic Law    Determined the atomic number of each of the elements.  He modified the ‘Mendeleev’s Periodic law’ and stated that the properties of the elements very periodically with their atomic numbers.      
Bohr    Present form or
Long form of Periodic Table (Bohr’s Table)    Bsed upon the electronic configuration of elements.   
Long form of periodic table consists of 7-Peroids, 18-Groups. Based on electronic configuration Periodic table is divided as:

        General electronic configuration      
1    s – Block    ns1 to 2      
2    p – Block    ns2 np1 to 6      
3    d – Block    (n-1)d1 to 10 ns1 or 2      
4    f – Block    (n-2)f1 to 14 (n-1) 0 or 1 ns2   
        Based on properties it is divided into :
Representative elements : both s and p blocks not zero group.
Transition elements : d – block elements not Zn, Cd, Hg
Inner transition elements : f - blocks
Nobel gases : Zero group elements.
Position of lanthanoids is III(B) – group 6th period.
Actionoids : III(B) group 7th period.
Periodicity : In the periodic table the properties of elements change gradually with change in their electronic configuration.  This trend repeats itself at regular intervals.  This repetition of a character is called periodicity and such properties are called periodic properties in the periodic table.

104 elements occur as solids
11 elements occur as gases
2 elements occur as liuid
11 elements occur as non-metals
6 elements occur as noble gases
7 elements occurs as metalloids
In the modern periodic table around 118 elements.

Periodic Properties    Period    Group      
Atomic radius    Decrease    Increase      
Ionsation enthalpy    Increase    Decrease      
Electron affinity    Increase    Decrease      
Electron Negativity    Increase    Decrease      
Metallic character    Decrease    Increase      
Non-Metallic character    Increase    Decrease      
Reducing character    Decrease    Increase      
Oxidising character    Increase    Decrease   
In the periodic table highest i.p is He
Highest electron affinity is Cl2
Highest electro negativity is F2   
Ionisatin Potential : The minimum energy required to remove the loosely bound electron from an isolated gaseous atom to converted into a gaseous ion is called ionization energy.
Atomic radius : Atomic radius is the distance between the centre of the atomic nucleus and the electron cloud of the outermost energy level.
Electron gain enthalpy : The amount of energy release when an electron is added to a neutral gaseous atom to convert it into a negative ion.
Electro negativity : The tendency of the atom of an element to attract the shared electron pairs more towards if self in a netero nuclear diatomic molecule.
Electrolysis : It is a process of decomposition of an elecrolyte by passage of electricity through its aqueous solution or molten state.  The apparatus used is called an electrolytic cell.
        The electode which is connected to the positive pole of the battery is called anode and the negative ions which move towards it are called anions.  The electode which is connected to the negative pole of the battery is called cathode and the positive ions which move towards it are called cations.
Eg: dissociation
      H2O→HΘ  + OHΘ   
At cathode : 2HΘ+2e-  → H2 (or) 4HΘ + 4e- → 2H2
At anode : 2HΘ → 2H2O + O2 + 4e-
Overall reaction : 2H2O →2H2↑ + O2↑
Faraday’s law’s :
1st Law : the weight of the ion deposited on an electrode is directly proportional to the quantity of electricity passed.
    W ∞ Q
    W = ZQ
    W = Z x C x t
               Q – Quantity of electricity in coulombs
               C – Current in amperes
                t – time in sec.,
                Z – Electrochemical equivalent.
2nd Law : when same quantity of electricity is passed through the solution of different electrolytes weight of ion deposited are directly proportional to their chemical equivalent.
                   e.g :  =       
                         1 F = 96500 C
                    Electro chemical equivalent =
Oxidation :
(i) Which involves addition of oxygen or other electro negative element. Or removal of hydrogen or any other electro positive element
(ii) involves loss of electrons.
(iii) results in the increase in oxidation number of its atoms.
Oxidizing agent or oxidant :
Supplies oxygen or any other electro negative element removes hydrogen or other electro positive element or
Can readily accept electrons from other substances.
The oxidation number of whose atom decreases.
Reduction :
Addition of hydrogen
Removal of oxygen
Gain of electro negative element results in the decrease in oxidation number.
Reducing agent or reductant :
Supplies hydrogen or remove oxygen readily donate electrons.
Oxidation number of whose atoms increase.
Redox reaction: a reaction which involve oxidation or reduction are called redox reactions.
Eg: 4HCl + MnO2 → MnCl2 + Cl2 + 2H2O
       HCl → Cl2 Oxidised
       MnO2 → MnCl2 reduced
                  O.S :    H = +1                             CN + -1
                              Cl- , F –  Br-,   I- = -1        O = -2

Electrovalent or Ionic bond : an ionic bond is the electrostatic force of attraction between oppositely charged ions.
Ionic bon is formed by the complete transfer of one or more electrons from one atom to another.
The atom which loses electrons changes into positively charged ion (cation) and the atom that gains electrons changes into negatively charged ion (anion).
Formation of Sodium Chloride
The electronic configuration of sodium (Z=11) is 2,8,1.  It has only one electron in the outermost shell.  By losing this single electron it can attain the noble gas configuration of the nearest noble gas, neon (2,8).
The electronic configuration of chloride (Z=17) is 2,8,7.  By gaining one electron, it can attain the noble gas configuration of the nearest noble gas, argon (2,8,8).
During formation of sodium chloride by combination of sodium and chlorine, one electron from sodium atom is transferred to chlorine atom and both of them attain stable octed.
Properties of electrovalent compound: the compouns in which the constituent particles are held by ionic bond are known as electrovalent or ionic compouns.  The characteristic properties of ionic compounds are described below :
Physical state : all ionic compounds are solids at room temperature.  They are crystalline in nature.
High melting and boiling points : Ionic compounds have strong electrostatic force of attraction between oppositely charged ions. A large amount of energy is required to overcome the strong attraction between the ions. Therefore, they possess high melting and boiling points.
Electrical conductivity : Ionic compounds do not conduct electricity in solid state because ions are held tightly by strong attractive forces and are not free to move.  However, ionic solids conduct electricity in molten state or in solution form.  In molten state or in solution form ions become free to move and hence conduct electricity.
Solubility : Ionic compounds are soluble in polar solvents such as water but are insoluble in non-polar solvents such as benzene, hexane, etc.
Ionic reaction : the chemical reactions between ionic solids involve regrouping of ions in their aqueous solutions.  Such reactions take place almost instantaneously.  For example, when aqueous solutions of silver nitrate and sodium chloride are mixed, a white precipitate of silver chloride is formed immediately.
           NaCl (aq) + AgNO3(aq) → AgCl(s) ↓ + NaNO3 (aq)
Covalent Bond : A covalent bond is the force of attraction that arises due to mutual sharing of electrons between two atoms.
Types of covalent bonds : Covalent bonds may be classified as single, double or triple covalent bond depending upon the number of shared pairs of electrons between the two atoms.
A single covalent bond is formed by sharing of a single pair of electrons between the two atoms.  It is represented by a single line (-) between the two atoms.
A double covalent bond is formed by sharing of two pairs of electrons between the two atoms.  It is represented by a pair of lines (=) between the two atoms.
A triple covalent bond is formed by sharing of three pairs of electrons between the two atoms.  It is represented by three lines (≡) between the two atoms.
      Properties of covalent compounds:
Physical state : Covalent compounds are generally gases or liquids at room temperature.  Many covalent compounds are in the form of low melting solids.
Low melting and boiling points : The covalent compounds consist of molecules as constituent particles which are held by weak interparticle forces.  Therefore, covalent compounds have low melting and boiling points.
Electrical conductivity : Covalent compounds are generally bad conductors of electricity.  Covalent compounds consist of neutral molecules and hence they do not conduct electricity.
However, some covalent compounds having polar molecules split into ions, when dissolved in water and hence conduct electricity.
Solubility : Covalent compounds are generally insoluble in polar solvents such as water but are soluble in non-polar solvents such as benzene, hexane, ether, etc.
Molecular reactions : Covalent compounds are composed of molecules in which atoms are held by strong covalent bonds.  Reactions of covalent compounds involve breaking of bonds in reactant molecules and formation of new bonds in product molecules.  This is a slow process and hence, reactions between covalent compounds are generally slow.
Coordinate bond : A coordinate bond is also formed by sharing of electrons between two atoms but in this case the shared pair of electrons is contributed by only one of the atoms.  The atom which provides the electron pair for sharing is called the donor atom while the atom that simply participates in sharing is called the acceptor atom.  Coordinate bond is represented by an arrow pointing from donor towards acceptor atom.
Some examples of compounds containing dative bonds are given below :
Ozone molecule
Nitrogen dioxide molecule
A coordinate bond, once formed, cannot be distinguished from a covalent bond.
Carbon exists in nature in many forms. Diamonds and graphite are pure crystalline forms of carbon.  Carbon is present in all living beings in the form of complex molecules.
The elecrinic configuration of carbon is .  It has four electrons in the valence shell.
Carbon atom completes its octet by sharing four electrons with other atoms. It exhibits tetravalency.
Occurrence : carbon ranks seventeenth in the order of abundance in the earth’s crust.  It is the second most abundqnt element in the human body.  Carbon occurs in free state as well as in combined state in nature.  In free state, it occurs in the crystalline form of diamond and graphite and in amorphous for as coal.

In combined state carbon occurs in the following forms:
All living being contain carbon in the form of carbohydrates, proteins and other biomolecules.
It occurs as hydrocarbons in the form of petroleum, natural gas, marsh gas, Coal also contains a large number of hydrocarbons.
It occurs in the for carbonates such as chalk, marble, limestone(CaCO3) dolomite (CaCO3.MgCO3), spathic ore of iron (FeCO3), calamine (ZnCO3).
Carbon occurs as oxides, carbon dioxide and carbon monoxide in atmosphere.  Air contains about 0.03% CO2 by volume.  Carbon dioxide is also present in dissolved form in water bodies where it exists as carbonic acid.
Allotropy :
The existence of an element in more than one form in same physical state, having different physical properties but same chemical properties is called allotropy.
Carbon exists in many allotropic form, crystalline as well as amorphous.  Diamond and graphite are the two crystalline allotropic forms of cabon.  Coke, charcoal, lamp black or soot are the amorphous or non-crystalline forms of cabon,
           Crystalline forms               Amorphous forms
Diamond         Graphite    Coke    Charcoal      Lamp Black                                                                                      (Soot)
Crystalline forms of carbon : diamond and graphite are the two crystalline forms of carbon. The two forms of cabon are chemically identical though they have different physical features. The difference in properties of diamond and graphite is due to difference in the arrangement of atoms in diamond and graphite.
Diamond : The weight of diamond is expressed as carats.  One carat is equal to 200 mg or 0.2g
Preparation of artificaial Diamonds : in ordr to meet the demond of diamonds in various industries diamonds have been prepared artificially.  Graphit can be converted into diamonds by the action of high temperature ( 3000oC) and high pressure in the presence of transition metals (Such as platinum).  The artificaila diamonds, however, are small in size and generally grey in colour and hence cannot be used as gems.  These are used for making cutting and grinding tools.
Structure of Diamond: In diamond each carbon atom utilizes its for valence electrons for the fomation of single covalent bonds with four other carbonatoms.  Thus, there is strong three dimensional network of covalent bonds in which each carbon atom is tetrahedrally surrounded by four carbon atoms.
Properties of Diamond:
Pure diamond is colourless and transparent.  However, presence of impurities imparts calour to the diamond.  For example, black diamonds (carbonado) contain traces of graphite.
Diamond is very hard.  Diamond is hardest substance that occurs in nature.  Because of its hardness it is used in making cutting and grinding tools.
Diamand has a high refractive index (2.45).  due to hig refractive index.
Density of diamond is quite high (3.51g cm-3 or 3510 Kg m-3).
Diamond is bad conductor of heat and electricity.
Natural diamond is transparent to X-rays.
Diamond has a very high melting point. High melting point of diamond is due to strong network of covalent bonds which holds various carbon atoms together.
Effect of heat.  It resists the action of heat to some extent.
However, when strongly heated (  800oC) in the presence of oxygen it foms carbon dioxide leaving behind no residue.    C + O2 →CO2
Chemical reactivity.  Diamond does not react with acids, alkalis and organic solvents under ordinary conditions.  When heated with sodium carbonate at high temperature, it is converted to carbon monoxide.
Graphite (Plumbago or Black lead)
Preparation : Graphite is manufactured by Acheson process.  In this process a mixture of coke and a little sand is heated in an electric furnace at about 3000oC for 20-30 hours.  Silicon carbide (SiC) is formed as the intermediate product.  Silicon carbide on decomposition and graphite.  Silicon volatilizes off whereas graphite is left behind.
                 SiO2     +     3C   →   2CO  +   SiC
                                                                Silicon carbide
                 SiC    →   Si↑       +       C
Structure of Graphite : In graphite, carbon atoms are in flat sheets and within the sheet, they are arranged in hexagons.  Each carbon atom in graphite is directly linked to only three carbon atoms through covalent bonds.  Therefore, of the four valence electrons in a carbon atom only three are used for bonding and the fourth is relatively free and can move from one atom to the other.  The layers are held by comparatively weak forces.  As a result, the layers are separated by large distances and can easily slide one over the other.  The distance between layers is more than double the distance between carbon atoms.  The density of graphite lower than diamond and also the slippery nature of graphite.

Properties of Graphite :
Graphite is a black opaque solid with metallic luster.  It is very soft and feels greasy.  Greasy feeling of graphite is due to ease with which layers can slide one over the other in graphite.  Since graphite marks paper black, it is also known as black lead.
Density of graphite is 2.25g/cm3 which is less than the diamond.
Graphite is good conductor of heat and electricity.
Graphite changes to diamond at a temperature of about 3000o C and a pressure of about 50,000 atm.  In the presence of oxygen graphite burns at about 800oC to form carbon dioxide.
Graphite does not react with dilute acids or alkalis.  When heated with concentrated nitric acid it yields graphitic acid, a greenish yellow insoluble acidic substance.
Uses of Graphite :
Graphite is good conductor of electricity and is inert.
Therefore it is used for making carbon electrodes in electrolytic cells and in dry cells.
 A mixture of graphite and clay is used for making lead in lead pencils.  When lead pencil is pressed over paper some of the loosely held layers of graphite are left on paper thus making a mark on the paper.
Graphite is used as lubricant either as a powder or as a dispersion in oil (oil-dag) or as a dispersion in water (aqua-dag).
Because of its high melting point, inert nature and ability to conduct heat it is used for making refractory crucibles.  Crucibles made of graphite are not attacked by dilute acids or fused alkalis.
Graphite does not absorb neutrons and hence is used as moderator in nuclear reactors.
Graphite is a component of printers ink.
Graphite under the effect of high temperature and high pressure can be converted into diamonds.
Amorphous forms of Carbon :
Coke : Coke is obtained by destructive distillation of coal.  It is mainly Carbon  (above 98%). It is a bad conductor of heat and electricity and it is a good reducing agent.
Gas carbon : Gas carbon is formed as a deposit on the walls of the iron retorts in which destructive distillation of coal is carried out.  It is very pure form of carbon.  It is very hard and is good conductor of electricity.
Wood charcoal :  wood charcoal is prepared by the destructive distillation of wood.  Charcoal is  bad conductor of heat and electricity.
Sugar charcoal : Sugar charcoal is the purest form of amorphous carbon.  It can prepared by destructive distillation of cane-sugar.  It can also be prepared by dehydration of cane-sugar by treating with concentrated sulphuric acid. Sugar charcoal is used in the manufacture of artificial diamonds.
Bone charcoal or Animal charcoal : Bone charcoal is prepared by destructive distillation of bones.  It contains about 10% carbon and the remaining 90% is mainly calcium phosphate. Animal charcoal is highly porous and is good adsorbent for colouring matter.
Lamp Balck or soot : Lamp black or soot is produced when carbon rich materials such as turpentine oil, vegetable oil, and kerosene are burnt in an insufficient supply of air.
Lamp black is used in the manufacture of Black paints, carbon paper, shoe polish, typewriter ribbons, printer’s ink, rubber tyres and Indian ink.
Hydrocarbons and their classification:
The organic compounds which contain only carbon and hydrogen are called hydrocarbons.
Hydrocarbons may be classified as saturated or unsaturated depending upon whether they contain only single bonds or multiple bonds.
Saturated Hydrocarbons : Saturated hydrocarbons are those hydrocarbons in which each carbon atom is bonded to other atoms by only single covalent bonds. 
In saturated hydrocarbons, each carbon atom is directly attached to four atoms.  The open chain saturated hydrocarbons are known as alkanes. 
Alkanes general formula is CnH2n + 2.
Unsaturated Hydrocarbon : Unsaturated hydrocarbons are those hydrocarbons in which ther is at least one carbon-carbon double bond or triple bond.
Unsaturated hydrocarbons containing carbon-carbon double bond are known as alkenes while those containing carbon-carbon triple bond are known as alkynes.  General formula of alkenes is CnH2n while that of alkynes is CnH2n-2.

The substances that dissolve in water to give conducting solutions are called electrolytes.  All electrolytes can be classified into three types : acids, bases and salts.  The properties of aqueous solutions of each class of compound are given below :

Properties of an Acidic solution    Properties of a basic solution    Properties of a salt solution      
Tastes sour.
Reacts with metals such as zinc, magnesium, etc., liberating hydrogen gas
Changes the colour of litumus form blue to red
Conducts electricity.    Tastes bitter, feels slippery.
Reacts with an acidic solution to destroy or neutralize the properties characteristic of an acid
Changes the colour of litmus from red to blue
Conducts electricity.    Testes salty.
The colour of the litmus solution usually does not change when added to a salt solution.
Conducts electricity.   
Acids :
According to Arrhenius concept : An acid is a compound which when dissolved in water furnishes hydrogen ions (H+).
When an acid such as hydrochloric acid (HCl) dissolves in water, almost all of it ionizes.  This type of acids are known as strong acids.
On the other hand, when acetic acid dissolves in water,  only a small fraction of the molecules ionizes.  Such an acid is called a weak acid.
            HCl → H+ + Cl-                 …………..Strong acid
      CH3COOH→ H+ + CH3COO-        …………..Weak acid

Strong Acids    Weak acids      
Hydrocloric acid :HCl
Nitric acid : HNO3
Sulphuric acid : H2SO4
Hydrobromic acid : HBr
Hydroiodic acid : HI
Perchloric acid : HClO4    Acetic acid : CH3COOH
Phorphoric acid : H3PO4
Boric acid : H3BO3
Carbonic acid : H2CO3
Formic acid : HCOOH
Oxalic acid : (COOH)2   
Classification of Acids : Acids can be classified on the basis of various factors as discussed below :
Depending on the Basicity : Basicity of an acid is the number of H+ ions that a molecule of the acid furnishes on complete dissociation. Eg: H2SO4
Monobasic acids : Acids which produce only one hydrogen ion per molecule on dissociation are known as monobasic acids. Eg: HCl
Dibasic acids : Acids which produce two hydrogen ions per molecule on dissociation are known as dibasic acids. Eg : H2SO4
Tribasic acids : Acids which produce three hydrogen ions per molecule on dissociation are knwn as tribasic acids. Eg: H3PO4
Depending on the strength : depending on the strength, acids are classified as strong acids and weak acids.
Strong acids : strong acids are the acids which are almost completely ionized in their aqueous solutions.  Eg: H2SO4 , HCl, HNO3
Weak acids : weak acids are the acids which are only slightly ionized in their aqueous solutions.
Physical properties
Acids have a sour taste.
Strong acids such as sulphuric acid, nitric acid etc., are highly corrosive in nature and can burn the skin.  Therefore, these acids should not be brought in contact with skin or clothes.
They are electrolytes i.e. they conduct electricity in their aqueous solutions.
Acids impart specific colour to the acid-base indicators.

Indicator    Colour in Acidic Medium    Colour in Basic Medium      
Litmus solution    Red    Blue      
Methyl orange    Pink    Orange      
Phenolphthalein    Colourless    Pink      
Methyl red    Yellow    Red    
Bases: A base  is a compound which furnishes hydroxyl ions in aqueous solution.
Oxides and hydroxides of metals generally act as bases.  Some examples of bases are : NaOH, KOH, Ba(OH)2, CaO, Fe(OH)3.
Classification of Bases :
On the basis of acidity : Acidity of a base is the number of hydroxyl ions which one molecule of the base can furnish in aqueous solution on complete dissociation.
Depending upon the acidity, bases are classified as monoacidic, diacidic, triacidic bases.
Monoacidic bases: Bases which produce only one hydroxyl ion per molecule on dissociation in their aqueous solutions are known as monoacidic bases.
Eg : KOH (aq) → K+ (aq) + OH- (aq)
Diacidic bases : Bases which produce two hydroxyl ions per molecule on dissociation are known as diacidic bases.
Eg : Ca(OH)2
Triacidic bases : Bases which produce three hydroxyl ions per molecule on dissociation in their aqueous solutions are known as triacidic bases.
    Eg: Al(OH)3
Depending on the strength : depending on the strength, bases are classified as strong bases and weak bases.
Strong bases : Strong bases are the bases which are almost completely ionized in their aqueous solutions.
    Examples : NaOH, KOH, Ba(OH)2
Weak bases : bases which are only slightly ionized in their aqueous solutions are known as weak bases.
    Example : NH4OH , Ca(OH)2,  Fe(OH)3
Properties of bases :
Bases have a bitter taste and are slippery to touch.
Strong bases such as caustic soda (NaOH) and caustic potash are corrositive in nature and can harm the skin.
Alkalies are good conductors of electricity.
Indicator properties
They turn red litmus blue
They impart pin colour to phenolphthalein.
They impart yellow colour to methyl orange.
They impart red colour to methyl red.
Neutralisation : Neutralisation is the reaction between an acid and a base resulting information of salt and water.
                   HCl     +      NaOH    →    NaCl     +    H2O
                 Acid     +      Base      →    Salt        + Water
Some practical appications of Neutralisation
A person suffering from hyperacidity is advise to take antacid tablets of antacid suspension.  Antacid preparations containmagnesium hyroxide as theactie component which neutralises the excess acid present in the stomach.
     Mg(OH)2  + 2HCl → MgCl2 + 2H2O

In acidic soils, slaked lime is addedto reduce acidity.
     Ca(OH)2   +    H2SO4        →     CaSO4 + 2H2O
Slaked lime    Sulphuric acid
   (Base)               (Acid)
The sting of ants and bees contains formic acid.  It is neutralised by rubbing soap or dilute ammonia solution.
The sting of yeow wasps contains an alkali.  It is neutralised by rubbing dilute acetic acid.
The pH Scale :
The concentration of hydrogen ions in solution is expressed in terms of pH units.
The pH of a solution is defined as the negative logarithm of hydrogen ion concentration in moles per litre.
pH = -log[H+]
The pH scale is a continuous scale and the values pH normally lie between 0 and 14.
[H+] = [OH-] = 10-7 mole/litre at 25oC.

Therefore pH of pure water or a neutral solution at 25oC is given as :
pH = -log[10-7] = 7
thus, pH of pure water at 25oC is equal to 7.
In pure water, [OH-] = [H+] = 10-7 mole/litre.
For neutral soutions : [H+] = [OH-]
For acidic solutions : [H+] > [OH-]
For basic soutions   : [H+] < [OH-]
For pure water or neutral soutions, pH = 7
For acidic solution pH < 7
For basic solutions pH > 7
Uses of Acids :
Sulphuric acid : Manufacture of fertilizers, chemicals, petroleum refining, dyes, drugs, explosives, dehydrating agent, etc.
Nitric acid : Manufacture of fertilizers, chemicals, explosives, dyes, drugs, in metallurgy, etc.
Hydrochloric acid : Picking and metal cleaning, acidizing of petroleum wells, food processing, in painting industry, etc.
Acetic acid : Manufacture of plastics, dyes, insecticides, food additive (as vinegar), etc.
Tartaric acid : In baking powder, tanning, ceramics, textile industry, silvering mirrors, etc.
Oxalic acid : General metal and equipment cleaning, leather tanning, bleaching of textiles, etc.
Citric acid : Soft drinks, health salts, acidifier, medicines, antioxidant in foods, etc.
Boric acid : Heat resistant glass, water solution as eye wash, fungus control in citrus fruits, etc.
Benzoic acid : Food preservatives, flavours, perfumes, etc.
Lactic acid : Foods and beverages, tanning, plastics and textiles, etc.
Uses of Bases :
Sodium hydroxide : Paper, soap, medicine, textile processing, vegetable oil refining, regenerating ion exchange resins, etc.
Potassium hydroxide : Soap, medicine, electrolyte in alkaline storage batteries, etc.
Ammonium hydroxide : Taxtiles, rubber, fertilizers, photography, fire-proofing wood, exposives, ceramics, detergents, food additives, household cleanser’s, etc.
Aluminium hydroxide: Water purification, dyeing mordant, water-proofing fabrics, medicine, manufacture of glass, fire extinguishers, etc.
Magnesium hydroxide : As an antacid to remove acidity from stomach, sugar refining, drying agent, in foods as alkali, etc.
Salts : A salt is a compound formed by replacement of either all or a part of the ionisable hydrogen atoms of an acid by some other cation.
A salt is formed by neutralisation of an acid by a base.
Acid + Base                      Salt + Water
For example, sodium chloride (NaCl) is formed by neutralisation of hydrochloric acid with sodium hydroxide.
HCl + NaOH                     NaCl + H2O
Acid   Base                       Salt      Water
Classification of Salts :
Normal Salts : Normal salts are the salts formed by complete replacement of all the ionisable hydrogen atoms of an acid by metallic or ammonium ions.
Some examples of normal salts : NaCl, KNO3, Na2CO3, Na2SO2, (NH4)3PO4.
Acid Salts : Acid salts are the salts formed by partial replacement of ionisable hydrogen atoms by metal or ammonium ions.
Some examples of acid salts : NaHSO4, NaHCO3, KH2PO4, K2HPO4.
Basic Salts : Basic salts are the salts formed by partioal replacement of hydroxyl groups of a diacid base or a triacid base by some other anion.
Some examples of basic salts : Basic lead chloride Pb(OH)Cl, basic magnesium bromide Mg(OH)Br.
Uses of Salts :
Sodium chloride (common salt) : used in food items and in the manufacture of sodium, caustic soda and washing soda.
Sodium carbonate (washing soda) : for water softening and washing.
Sodium bicarbonate (baking soda) : In health drinks and baking powders.
Sodium thiosulphate (hypo) : As fixer in photography.
Potash alum : In dyeing and in the purification of water.
Silver nitrate (lunar caustic) : For making mirrors and as laboratory reagent.
Copper sulphate (blue vitriol) : For electro-refining of copper and as fungicide.
Silver chloride : In photography.
Sodium cyanide : Extraction of silver.
Sodium hypochlorite : As bleaching agent.
Synthetic Fibres and Plastics : A fibre is a thread or a filament from which clothe is made.  If synthesized by humans, it is known as synthetic fibre and if obtained from plants and animals it is known as natural fibre.  The materials which are obtained from natural or artificial sources, by weaving or knitting the fibres re called fabrics.
Some important synthetic Fibres are : 1. Rayon or artificial silk  2. Nylon  3, Polyesters.
Chemistry of Fibres : Chemically fibres are polymers.  Polymer is a Macro molecule with high molecular weight, which is formed by union of a large number of small simple units called Monomers in a fixed arrangement.  These units are connected by covalent chemical bonds.
Examples :
Cellulose is a natural polymer of glucose.
Polythene is a polymer of ethene.

Some more types of Polymers :
Thermo plastic polymers : the polymers soften on heating but regain their original properties on cooling are thermo plastic polymers.
Example : Polythene, Polystyrene.
Thermo setting polymers : the polymers have permanent shape and properties and are not effected by heat are thermo setting polymers.
Example : Bakelite, Melamine, etc.
Nearly 4/5 of the Earth’s surface is covered with H2O.
65% - 70% of human body is constituted by water.
The water suitable for drinking is called potable water.
Water is compound of hydrogen and oxygen atoms combine together in the ratio of 2 : 1.
Due to anomalous behaviour water has minimum volume and maximum density at 4o C.
Water cycle : Stages of water cycle are : 1.Evaparation, 2. Condensation,                       3. Precipitation, 4. Surface runoff, 5. Infiltration,     6. Transpiration.
Specific heat capacity of water : Specific heat is the amount of heat absorbed when 1gm of the substance is heated through 1oC.
Soft water                                                Hard water
          Temporaty hard water               Permanent hard water
Soft water : A sample of ground water which freely lathers with soap solution.
Hard water : Hard water does not give ood lather with soap or forms sticky scam.

    Temporary hard water    Permanent hard water      
Reaction with soap    which ordinarily forms scum with soap solution, but on boiling it gives lather    Even on boiling and then treating with soap solution does not lather but forms a scum.      
Cause of salts    Ca(HCO3)2 
Mg(HCO3)2    CaCl2, CaSO4
MgCl2, MgSO4      
Removal of hardness    Clark’s method [Ca(OH)2]
By boiling
By adding alum    By Na2CO3. 10H2O NaOH
Permutite process : Na2Al2Si2O8.XH2O
Ion Exchange process
Calgon’s process Na2[Na4(PO3)6]
Sodium hexa meta phosphate   
Physical properties of H2O :
Pure water is a colourless, tasteless and odourless liquid.
Pure water boils at 100oC at a pressure of 76 cm of Hg and Freezes at 0oC.
Fuels : Any cheap magterial which burns in air or oxygen with the release of large amount of heat and light energy is called fuel.
Fuel + Oxygen → CO2 + H2O + Heat
Produced pollutants : CO2, CO, SO2, smoke unburnt carbon particles, lead compunds.
Fuels are classified in to solids, liquids, gaseous.
1. wood : It is the commonly used fuel in rural areas in India.  It produces a lot of smoke an burning and its calorific value is low.
2. Cow dung cakes : They are usually made in rural areas by farmers who keep animals.  These cakes are dried in the sun and are used as fuel.  They also produce a lot of smoke.
3. Coal : it is a fossil fuel.  It is mainly used in industries.  It also produced lots of smoke and ash after burning.
4. LPG : Liquefied Petroleum Gas mainly contains butane gas.  It is obtained by the fractional distillation of petrolium.
5. CNG : Compressed Natural Gas mainly contains methane gas.  It is used as a fuel in CNG buses and industries.  It is also being supplied through pipes directly to homes as a fuel.  It is good because it is less pollution.