EDUCATION IN PAKISTAN

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                      CHEMISTRY NOTES FOR 9th SCIENCE CLASS                            
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CHAPTER 1                    INTRODUCTION TO CHEMISTRY 
 
Q1: What are the branches of chemistry? 
Ans: The five branches of chmistry are as follows: 
1: Organic chemistry:-Organic chemistry is the study of carbon containing substances and the synthesis of such material. many consumer products are organic in nature. 
2: Inorganic chemistry: Inorganic chemistry is the chrmistry of element and their compounds except those of carbon-hydrogen compounds and their derivatives. 
3: Physical chemistry: Physical chemistry is the branch of chemistry which deals with the forces and principles involved in the combination of atoms and molecules. 
4: Analytical chemistry:Analytical chemistry is the study of method and techniques used to determind the kind and quantity of various component in a given substance. 
5: Biochemistry: Biochemistry is the chemistry of living organisms such as plants and animals. 
Q2: Define mass? 
Ans:Mass:-The quantity of matter contained in a body is called its mass. 
            its s.i unit is "kilogram" and its symbol is "m". 
Q3: Define volume? 
Ans: Volume:- Space occupaid by a body is known as volume. 
      its s.i unit is "m3" and its symbol is "v". 
Q4: Define density? 
Ans: Density:-It is define as ratio between mass and volume. mass per unit volume is known as density. 
       mathematically: d=m v 
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              its s.i unit is kg/m3. density of solid and liquid usually expressed in g/cm3 and that of gases as g/dm3. 
Q5: Define temperature? 
Ans: Temperature:- Temperature is a measureof the intensityof heat. it is thus a measure of the degree of hotness and coldness in a body. 
Q6: Define specific gravity? 
Ans: Specific gravity:- The specific gravity of a substance is the ratio of its mass to the mass of an equal volume of water at a specified temperature. 
    Specific gravity =                  mass of substance 
                                       mass of an equal volume of water 
specific gravity of a substance ia a ratio between two same quantites and thenfore has no unit. 
Q7: Define element? 
Ans: Element:- An element is defined as a substance in which all the atoms are chemically indentical havingsame atomic number. for example: iron: silver: gold: copper: oxygen: hydrogen: etc. 
Q8: Define compound? 
Ans: Compound:- A compound is pure substances which consist of two or more element chemically combined in a fixed proportion by mass.compound can be broken down by chemical method. 
for example:water(H2O); salt(NaCl). 
Q9: Define mixture? 
Ans: Mixture:-A mixture contains two or more element which can easily be seprated by physical method. the component doesnot lose its chemical propertse. 
for example: soil; rock; e.t.c. 
Q10: Define valency? 
Ans: Valency:-The chemical combining capacity of an atom or an element with another element is called valency. 
Q11: Define atom? 
Ans: Atom:-It is the smallest particle of an element. it does not exist freely into nature. it is the unit of an element involved in a chemical reaction. 
Q12: Define molecule? 
Ans: Molecule:- It is the combination of two or more atom. it can exist freely in the nature. 
Q13: Define mole? 
Ans: Mole:-The weight of an atom or a molecule expressed in grams is known as one mole. 
Q14: Define atomic mass? 
Ans: Atomic mass:-The atomic mass of an element is the average relative mass of the isotopes of that element referred to the atomic mass of carbon which is taken as 12.0000 amu. 
Q15: Define moleculer mass? 
Ans: Molecular mass:- The moleculer mass of an element when it exists in the form of moleculer or of a compound is the average mass of the moleculer as compound to one atom of 12C6. 
Q16: Define gram atomic mass? 
Ans: Gram atomic mass:- The weight of an atom expressed in gram is called gram atomic mass. it is also called gram atom. 
Q17: Define gram molecular mass? 
Ans: Gram molecular mass:- The weight of molecule expressed in gram is called gram molecular mass .it is also called gram molecule. 
Q18: Define avogadro’s number (n)? 
Ans: Avogadros number:-The number of particles contained in a mole is equal to 6.023*10 power 23 is known as avogadro number. 
Q19: Define low of constant composition with examples? 
Ans: Low of constant composition:-Proust formulate the low of constant composition in 1799 as that every pure sample of a particular chemical compound contain the same element combined in the same fixed proportion. it is also called the low of definite proportions. 
examples: 
1, He obtained several samples of copper carbonate from different sources and also prepared it through different methods in his laboratory. he found whatever source of method of preparation was used, it always had the same proportion of copper,carbon and oxygen by mass. 
2, He also mixed ten grams of lead with different amount of sulphur to make the grey solid lead sulphide. he always found that the lead sulphide had the same fixed percentage of lead and sulphur. 
Q20: Define heterogenous mixture? 
Ans: Heterogenous mixture: the mixture which donot have uniform composition throughout their mass,are called helerogenous mixture. 
Q21: Define homogenous mixture? 
Ans: Homogenous mixture: mixtures having uniform composition are called homogenous mixture. 
Q22: Differentiate between compound and mixture? 
Ans: 
                Compound                                                                                  Mixture 
 
<table border="1" style="width: 624px;"><tbody>
<tr><td valign="center">1:it is a pure substance. </td><td valign="center">1:it is an impure substance.</td></tr>
<tr><td valign="center">2:it cannot be saparated by physical methods.</td><td valign="center">2:it can be saparated into its componets by simple physical methods. </td></tr>
<tr><td valign="center">3:element forming compoundlose their original propertie-s.</td><td valign="center">3:substance making up themixture do not lose their original properties.</td></tr>
<tr><td valign="center">4:its composition is fixed. </td><td valign="center">4:its composition is not fixed.</td></tr>
<tr><td valign="center">5:the melting point and boiling point of compound are sharp and characteristic of each compound.</td><td valign="center">5:the melting point and boiling point of a mixture are not sharp.</td></tr>
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CHAPTER  2   CHEMICAL REACTIONS AND CHEMICAL EQUATIONS 
 
Q1: State law of conservation of mass (matter)? Give examples. 
Ans.: During any process, mass is neither created nor destroyed this law was put forward by a French chemist, lavoiser in 1785. 
 This law states that: 
Matter is neither created nor destroyed during a chemical reaction. 
During a chemical reaction, the total mass of the product is equal to the total mass of the reactants. 
Example no 1: 
When a piece of iron is left in moist air its surface gradually turns brown, the object gets rusted and gains mass. 
             4Fe+3O2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2Fe2O3 
The increase in mass is just the mass of oxygen. 
Example no 2 
When coal burns it leaves behind ash. The ash is lighter than coal. But the mass of coal will be equal to that of ash and the liberated carbon dioxide. 
             C+O2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />CO2 
Q2: state exothermic and endothermic reaction with examples? 
Ans: exothermic reaction:-Reaction in which heat energy is evolved is known as exothermic reaction in such reaction the system become warmer and neat potential energy of subtanses decreases. The enthalphy of product is less than the enthalphy of 
reactants. 
Examples:- 
When unslaked calcium oxide is added to water.the water becomes warm with formation of 
Slakeel time . in this reaction heat energy is released. 
Endothermic reaction:-Reaction in which heat energy is obsorbed is known as endothermic reaction . in such reaction enthalphy of reactants is lower than those of product. Since energy 
Is obsorbed during reaction the temerature of reaction decreases. (example are) 
Heat is obsorbed in the decomposition of calcium carbonate. In this reaction heating must be continous to decompase calcium carbonate. 
Q3: What are different types of reaction? Give chemical reaction of each type? 
Ans: Chemical reaction are of following types: 
1: Simple decomposition :-In this reaction a single compound is decomposed into two or more simple substance. 
2: Synthesis:-In this reaction two or more substance combine to from a single compound it is also known as addition reaction. 
3: Displacement:-In this reaction an atom or radical displaced by another in a compound. Such reaction depend upon the electropositive or electronegative nature of an atom or radical to displaced another. 
4: Double decomposition / displacement :-In this reaction the two reactants decompased  to form two new subtances by exchanging their radicals. 
5: Neutralization:-In this reaction , the hydrogen ion of an acid neutralized by the hydroxide ion of a base to from salt and water. 
6: Hydrolysis:-In this reaction the salt of either weak acid and base dissolve in water to from acid and base. 
 
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Chapter 3                       Water and solution 
 
Q1) Define solubility what are the factors which can affect solubility? 
Ans: Solubility:-"The solubility of a solute in a solvent at a particular temperature is the number of grams of solute necessary of saturate 100g of the solvent at that temperature." 
Factore of solubility 
1)Temperature:-it is often observed solubility of many solute the solution generally inereases in tempe rature for example, the solubility of potassium mitrate increases with temperatures the solubility of some solute decreases with the inerease in temperature such solute generallyheat when dissloved in water for example,calcium oxide is less soluble in hot water than in the cold state. 
gases are also more soluble in cold solvent than in hot solvent. 
2) Pressure:-Solubility of gases increases with the increase inpressure . carbon di oxide in filled in soda water bottles pressure. 
3) Nature of the solute and the solvent:-The solubility of polar compound is more in polar solvent and that of non-polar solvent in non-polar solvent. 
Q2) Define molarity? 
Ans: Molarity:-Molarity is a measure of the concentration of solution.it is denoted by "M"."it is define as the number of moles of solute dissolved per litre of solution(not solvent)". 
M= number of mole of solute 
      volume of solvent in dm3(L) 
Q3) What are electrolysis and non-electrolysis also give example of strong and weak electrolysis? 
Ans: Electrolysis:The substance which allow electricity to pass through their solution and are chemical decompose are called "electrolysis." 
example: acid,base,salt 
Non-electrolysis:-" These subtances which donot dissociate into ions when dissolved in water and donot wnduct electricity are known as non-electrolysis." 
example:sugar,solution,benzene. 
Strong electrolysis:-Those electrolysis which are highly dissociated and can conduct large current are known as"strong electrolysis". 
example: HCl, NaOH 
Weak electrolysis:Those electrolysis which are poorly dissociated and can conduct poor current are known as"weak electrolysis". 
example: acetic acid, mecuric chloride 
Q4)Define electrolysis? explain the prosis of electrolysis of copper chloride solution? 
Ans: Electrolysis:The movement of ion of an electrolyte and their deposition as neutral species at the electrodes under the influence of elctric current is known as "electrolysis". 
The electrolysis of aqueous copper chloride:When aqueous copper chloride is electrolysed between carbon electrodes copper is deposited at the cathode(negative electrode) & chlorine is given at the anode(positive electrode). 
                  Aqueous copper chloride contain copper ion and chloride ion. The copper ion beind positively charged move towards the cathode and the chloride ion beind negatively move towards the anode.The copper ion take up electrons from the cathode and deposit copper on it. 
Reaction at cathode: Cu++(aq)<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />+2e-Cu(s) 
Reaction at anode:     2Cl-(aq)<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />Cl2 + 2e- 
Q5) Define saturated,unsaturated and super saturated? 
Ans: Saturated: A saturated solution is the solution which contains maximum amount of solute that it can dissolve at a particular temperature. 
Unsaturated: An unsaturated solution is one which contains less amount of solute that it can held at a particular temperature. 
Super saturated:A super solution is one which contains more solute that it can theorically be held by the solvent at a particular temperature 
Q6) What do you mean by hard water and soft water? 
Ans: Soft water:-Water which produces lather with soap easily and do not produce insoluble curdy precipitate is called soft water. 
Hard water:-Water which produces insoluble curdy precipitate with soap and lather is not easily formed is called hard water. 
 
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Chapter 4                                   Acid,Bases and Salt 
 
Q1) What are acid?discribe various concept of acid?name five properties of acid with equation? 
Ans: Acid:-Those substance which  provide H+ ion in aqueous solution are known as 
"acid". 
Concept of acid:-many scientist proposed different theories about acid. Some of the important theories are given below. 
Arrhenious theory:-A sweedish scientist Arhenious define acid as "The substance which give hydrogen ion in water". 
Lowry and bronsted theory:-In 1923 lowry bronsted deifne acid as"The substance which donate or trend to donate a proton. 
                        In this example acidic.Accept donate proton to water which accept it. 
Lewis theory:- In american scientist named lewis in 1923 give an electronic defination about acid according to him "acid is that substnace which can accept alone pair of electron". 
example: AlCl3,BF3 and H3O 
can act of lewis acid because aluminium is short of two electron for completion of its valency shell and acceptimg it. 
Properties of acid: 
Physical properties: 
1) They have sour taste. 
2) They can turn blue litmus red. 
3) Aqueou solution of acid conduct electricity. 
Chemical properties: 
1) When an acid react with metal it produces salt and hydrogen gas. 
2) When an acid react with metal oxide it produce salt and water. 
3) When an acid react with base it produce salt and water. 
Q2) What are base?Describe various concept of base? name five properties of base with equation? 
Ans: Base:-Those substance which yield hydroxyl ion in aqueou solution are known as "base". 
Concept of base:- Important concept of base are as follows: 
Arrhenious theory:- The substance which give hydroxyl ion in water is known as base. 
Lowry and bronsted theory:-Base is a substance which accept or tend to accept a proton in a chemical reaction 
dissociation of HCl may be represented as 
Here HCl act as an acid of water as a base. 
Lewis theory:-A base is that substance which can donate alone pair of electron.Ammonia is a base because it donate electron pair of AlCl3. 
Properties of base:- 
Physical properties:- 
1) They have bitter taste. 
2) They turn red litmus blue. 
3) They conduct electricity. 
Chemical properties:- 
1)When base react with an acid it rpoduce salt and water. 
2) Base give ammonia gas when they are reacted with ammoniam salt. 
3) It react with aluminium to form sodium aluminate and hydrogen gas is evolved. 
Q3) What is Ph scale? 
Ans:- PH:-PH is defined as the logarithm of reciprocal of hydrogen ion concentration. 
PH= 1 
        H 
Q4) Define following iterm strong and weak acid and base,nutralization ,acidity of base and bascity of acid and crystallization? 
Ans:- Strong acid:- Those acid which have high percentage (more than 30 percentage) are strong acid. 
example: HCl, HNO3 etc 
Weak acid:- Those acid which have low  percentage of dissociation (less than 30 percentage) are weak acid. 
eaxmple:- HCN, CH3COOH etc 
Strong base:- Those acid which have high percentage of dissociation (more than 30 percentage) are strong base. 
example:- NaOH, KOH etc 
Weak base:-Those acid which have low  percentage of dissociation (less than 30 percentage) are weak base. 
example: NH4OH, Al(OH)3 etc 
Nutrallization:-This reaction between acid and base resulting information of a salt and water is called nutrallization. During nutrallization H+ and OH- ions which are responsible for characteristic of acid and base combine to form unionized water molecule. 
example: H+ +OH-<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />H2O 
Acidity of base:-The number of hydroxyl ions presents in a molecule of base for example KOH is mono acid base Ca(OH)2 is a diacid base where as is triacid base. 
Basicity of acid:- The number of replaceableor ionizable hydrogen atoms in the molecule of an acid is called basicity of the acid. 
Crystallization:- Crystal is a solid which possesses a definite geometrical shaped and the process by which there crystal are prepared is called crystallization. 
 
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Chapter 5                                           The period table 
Q1: Write down the general characteristic group of IA, VIIA and VIIIA? 
Ans:Group IA(ALKALI METAL): The alkali matels lithium, sodium, potassium, rubidium, cesium and francium are ligth metal.They are very reactive and chemically are strongly electropositively.As the group is decending there is a gradual decrease in ionization potential with an increase in the size of the atom.They contain one electron in their outer most shell and form ionic bonds by loss of valence electron.Compound of these metal were obtained from wood ashes. 
Group VIIA(HALOGEN FAMILY):-Flourine, chlorine, bromine and iodine constitute a group or family of element called the halogen, a term which means "salt formes". The halogen are very active non-metal and are very much a like  in their chemical properties.Each of the halogen has seven valence electron.Halogen are highly electronegative element and their electronegatively decrease down the group.Flourine and chlorine are gases at ordinary temperature bromine is a liquid and iodine is a solid. all the halogen exit as diatomic molecule. 
Group VIIIA(NOBLE GASES):-The element of group VIIIA are called "noble gases" or "inert gases" or "zero gases" element. They are monoatomic and low boiling gases.Since the outermost shell of these element are complete therefore these element are mostly  chemically unreactive.All the noble gases except radon are normally present in the atmosphere.They are mostly obtained from air by liquefaction process. 
Q2) What are transition element write four properties of them? 
Ans: Transition element:Element of group IB, IIB, through VIIB are known as transition element. They include the elem,ent scandium, yttrium, thanum and actinium and the two rare-earth series of element the lantanide and actinide series. 
properties: 
(1) These element have incomplete inner electron shell. 
(2) All transition element are metal. 
(3) The bond between the atom are very strong and they have melting points. 
(4) These compound are formed by coordinate covalent bond. 
 
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Chapter 6                          ATOMIC STRUCTURE 
Q1) Describe the postulates of dalton atomic theory?What are the draw backs in this theory? 
Ans:Dalton atomic theory:-The fundamental postulates of dalton atomic theory are stated below: 
1) Matter is composed of extremly tiny invisible particles called atom. 
2) Atom can neither be created or destroyed. 
3) Atom of a particular element are indentical in size shape mass and all other properties & differ from atom of other element in these propertoes. 
4) Chemical combination takes place between small whole number of atom. 
According to the latest research on the structure of atom &matter neutral particle following defeet are abserved in dalton atomic model. 
Drawbacks of dalton atomic theory:- 
1) Atom consist of charged particle called proton and electron & neutral particle called neutron. 
2) The atom of the same element may differ in their atomic mass and such atom of an element are called isotopes. 
3) The ratio between atom of various element in many molecules of the organic compound is not simple. 
4) Matter can be converted into energy by einstein equation E=mc2 
Q2) How was electron discovered? decribe in detail the experiment performed for the discovery of electron? 
Ans: Discovery of electron:-Electron is the smallest particle of atom.the most convising evidence for the existence of electron came from the experiment performed by crookers, faraday, and jjthomson.A high voltage electric current was pass through gases at a very low pressure(1mm of hg) in a dis charge tube.When high voltage is applied across the two metallic electrode sealed in a discharge tube the rays begin ti originate from cathode which are called cathode ray.These rays travel in straight line towards the anode.If an electric field is applied , these rays bend towards the positive pole which show their negative nature. 
Properties of cathode rays:- 
1) Cathode rays travel in straight line away from the cathode. 
2) Cathode rays are negatively charged as they bend towards the psoitve pole of the magnetic field. 
3) The rays upon striking glass or certain other material cause these material to glow. 
4) The charge to mass ratio (e/m) of those particle was found equal to that of electron. 
e/m = 1.76 * 10 power8 coulmob per gram 
5) The mass of each negative particle was found equal to 1/1837 of the lightest hydroden atom. 
On the basic of those properties it was concluded that cathode rays are negatively charged particle called electron. 
Q3) Discuss bohrs atomic model &describe its significance in atomic structure? 
Ans: Bohrs atomic model:- Neil bohr peoposed a new model for the structure of the atom in 1913.The salient feautures of this model are that. 
1) Electron revolve around the nuclus in fixed circular paths which he called orbit or energy level. 
2) As long as an electron revolve in a particular energy level it does not emit or absorb energy. 
3) When an electron absorb energy it moves to a higher energy level further away from the nucleus. When it lose energy it return to lower energy level closer to the nucleus & the energy is emitted as light. 
4) The electron loses a definite quantity of energy called quantium of energy when it jump down from an orbit of higher energy level to a lower energy level.The energy is emitted in the form of radiation. The frequency of the energy emitted is directly propotional to the difference in energy between the two level. 
5) The angular momentum (mvr)of an electron in any orbit is integral multiple of h/2x 
mvr = nh/2x 
Q4) Name the fundamental particle of an atom write the characteristic of each particle? 
Ans: fundamental particles of atom:- fundamental particle of an atom are: 
1)Electron:- 
1: It is a negatively charged particle. 
2: Its mass is equal to 9.11*10 power-31 kg 
3: The charge on electron is unit negatively or 1.6022*10power -19 coulomb 
4: Electron are present around the nucleus of an atom. 
2) Proton: 
1: It is a positively charged particle. 
2: Its mass is equal to 1.6726*10 power-27 kg 
3: The charge on proton is equal to that of electron. 
4: Proton are present in the nucleus of an atom. 
3) Neutron: 
1: Neutron has no charge. 
2: Its mass is equal to 1.67492*10 power-27 kg 
3: It is 1842 times beavier than an electron. 
4: Neutron are also present in the nucleus of an atom. 
 
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Chapter 7                                  Chemical bonding 
Q1) Explain ionic bond and covalent bound with any one example? 
Ans: Ionic bond:- It is a bond formed by the complete tranfer of electronsfrom one atom to the other atom. 
the atom which lose electron acquire posotive charge and the one which again which acquire negative charge. for example 1 
Consider the formation of NaCl:- In formation of naclmolecules one electron is trasefered from na atom to cl atom their by the octet of each atom is completed. 
Covalent bond :-It is the bond formed by the mutalsharing of electron between the tow bonded atoms. example. 
Formation of molecule:-Considered two hydrogen atoms. each has one electron in its outer most shell. thus the two atoms contribute there two electron to form a shared pair electron. the pair of shared electron is known as covalent bond. it is donated by H-H. 
Q2) Describe the types of covalent bond? 
Ans: Types of covalent bonds 
Single covalent bond:-A covalent bond formed by the  mutual sharing of one electron pair is called a covalent and is denoted by single short straight line.for example in H-Cl, H-H etc 
Double covalent bond:-A covalent bond formed by sharing of two electron pair  is denoted by two short  line.for example in O2, C2 etc 
Triple covalent bond:-A three electron pair bond is called a triple covalent bond and is donated by three short line.In nitrogen there is a triple covalent bond. 
Q3) Differentiate between ionic and covalent bond? 
Ans:                      Ionic bond                                                                                          Covalent bond 
<table border="1" cols="2" style="width: 100%px;"><tbody>
<tr><td>1: It is formed by the complete transfer of electron.</td><td>1: It is formed by the mutual sharing of electron.</td></tr>
<tr><td>2: In this bond one atom acquire negative charge.</td><td>2: No charges are developed on the two bonded atoms.</td></tr>
<tr><td>3: Ionic bond are strong.</td><td>3: Covalent bond are weak.</td></tr>
</tbody></table>
Q4)  Differentiate between ionic and covalent compound? 
Ans:                 Ionic compound                                                     Covalent compound 
<table border="1" cols="2" style="width: 100%px;"><tbody>
<tr><td>1: Ionic compound do not contain molecules.</td><td>1: Covalent compound contain molecules.</td></tr>
<tr><td>2: Ionic compound are mostly inorganic compound.</td><td>2: Covalent compound are mostly organic compound.</td></tr>
<tr><td>3: They are usually soluble in water.</td><td>3:They are usually insoluble in water.</td></tr>
<tr><td>4: They can conduct electricity.</td><td>4: They cannot conduct electricity.</td></tr>
<tr><td>5: They are non volatile in nature.</td><td>5: They are volatile in nature.</td></tr>
</tbody></table>
Q5) What is chemical bond ? 
 Ans: Chemical bond:  The attractive force which bonds atoms together is called chemical bond. 
Formation of chemical bond:When element reat to from a compound, the chemical bond are formed between atom. all chemical bond between atoms are formed by utilising the electron of outer most shell generally the atoms combine with are another in there way. 
1) By using electron. 
2)By gaining the electron. 
3)By sharing the electron. 
When the compound undergose chemical reaction the bond b/w the atoms are rearranged. 
 
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CHAPTER 8                HYDROGEN AND THE ACTIVE METAL 
q1) how hydrigen is prepared commercially and give its properties? 
ans) commercial hydrogen is relatively less pure and can be prepared by following methods. 
1) passing steam over red hot coke:- by passing steam over red hot coke we get. 
  C+H2O<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />CO+H2 
carbon monoxide can be seperate from the gaseous mixture by liquefying at a temperaturwe of -200c. 
2) by the electrolysis of water:- the purest but expensive hydrogen is obtained by the electrolysis of water in the presence of little acid. 
2H2O<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2H2+O2 
3) by thermal decomposition:-hydrogen is prepared by thermal decomposition of natural gas. 
CH4<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />C+2H2 
4) pure and relatively in expensive hydrogen is prepared by passing steam aver red hot ion. 
3Fe+4H2O<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" /> Fe3O4+4H2 
5) by heating a mixture of natural gas steam the presence of a suitable catalyst nickel. 
CH4+H2O<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />3H2+CO 
properties of hydrogen: 
a) physical properties:- 
1) hydrogen has got three isotopic forms known as protium ,deutrium and tritium. 
2) at room temperature hydrogen is a colourless, tastelessand odourless gas. 
3) molecular hydrogen is the lightest of all gases. 
b) chemical properties:- 
1) reducing agent:hydrogen is a very reducing agent it can reduce metallic oxides to metal easily,e.g. 
CuO+H2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />Cu+H2O 
2)reaction with non metal: hydrogen react with non metal like oxygen and nitrogen on heating. 
2H2+O2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2H2O 
3) reaction with helogen:hydrogen immediately react with halogen to give halides. 
H2+Cl2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2HCl 
q2) how aluminium is extracted from its ore.give its physical and chemical properties? 
ans) preperation:- it is prepared industrially by a procee called the hall beroult process. 
purification of ore:- naturally occuring bauxite contain impurities like silica and oxides of iron. the first step is obtained aluminium therefore involves the purification of the mineral. the natural bauxite is reacted with a hot concentrated solution of sodium hydroxide and form soluble sodium alminate .the impuritise remain undissolved and ore removed by filtration. aluminium hydroxide is then precipitate from the solution and is heated to regenerate pure aluminium oxide.. 
electrolysis of aluminium:- the pure aluminium oxide obtained by the above process is dissolved in a molten mixture of cryolite and calcium flouride at 950c. this molten mixture is electrolysed in a specially designed cell with carbon anode. the final result can be reperesented by the following simplified electrode reaction. 
Al2O3<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2Al+3O 
aluminium is liberated at the cathode and oxygen is liberated at the anode however the atomic oxygen released atthe carbon anode reacts with anode itself to produce carbondioxide gas. 
thus the carbon anodes constantly consumed during the process and they must be replaced at suitable intervals. 
PROPERTIES OF ALUMINIUM:- 
PHYSICAL PROPERTIES :- 
1)Aluminium has a silvery white lustrous shine. 
2)it is a good reflector of heat and light. 
3)it is a good conductor of heat and electricity. 
4)it has a melting point 66C 
CHEMICAL PROPERTIES :- 
ACTION OF AIR :-dry has no action .but in most air when aluminium powder is strongly heated it forms aluminium oxide. 
ACTION OF WATER :-cold water has no effect on pure aluminium. but aluminium powder decompose water at 100C liberating and forms. 
REACTION WITH ALKALIS :-aluminium react vigorously with strong alkalis eg to form aluminates along with hydrogen . 
Q3) what are isotopes?describe the isotopes of hydrogen? 
ans) isotopes are atom of same element with same atomic number but different mass number. 
isotopes of hydrogen: there are three isotopes of hydrogen i.e 
1)protium or ordinary hydrogen 
2)deutrium 
3)tritium 
1) protium(ordinary hydrogen):- it most frequently occur in nature. it is represented by 1H1. it has one electron in the nucleus and one electron in the k sheel. it occur to 99.98%. 
2) deutrium(heavy hydrogen):- it occur to very little extent. ordinary hydrogen contain about 1 part of deutrium in 7000 part of it. it is represented by 1H2 or D. it has one electron and one neutron in the nucleus and onen electron revolves in the k shell.it is usually present in the form of D2O (heavy water) in ordinary water is small amount. 
3) tritium:- it is the heviest isotopes of hydrogen and very varely occur in nature. it is represented by 1H3 or T . it has one proton and two neutron in the nucleus and one electron revolve in the k shell. it has radio active form of hydrogen. 
q4) how is sodium hydroxide manufactured electrolytically.give its important application. 
ans) sodium hydroxide commonly known as caustic soda is commonly manufactured by the electrolysis of solution sodium chloride which is commonly known as brine. 
in this electrolytic process nelsin cell is used. in this cell anode consist of graphite rod and a u shaped perforatedsteel cathode used.brine is added in the u tube which on electrolysis gives chloride anode and sodium at cathode sodium react with water to form sodium hydroxide(caustic soda). 
application of sodium hydroxide: 
1)it is an important labotaroy reagent. 
2)it is usedin paper industry. 
3)it is used in the refining of petroleum and oils. 
 
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chapter 9                       Iron,copper, zinc and lead 
q1) how is iron manufacture by blast furnace? 
ans)extraction of iron: iron metal is gradually extrated from its oxide ores by reducing them with carbon in the from of coal and coke. 
the charge,consisting of roasted ores,coke and limestone is fed into the top of the furnace.a preheated blast of air at about 1500c is blown into the furnace under pressure near to the bottom.the blast oxidizes the coketo carbondioxide. 
the reaction is highly exothermic considerable heatis librated which raises the temperature about 1900c in this region as the carbon dioxide passes upwards it react with more coke to form carbonmonoxide. 
the formation of carbon monoxide is an endothermic process and the temperature in this region falls to about 1100c .the carbon monoxide thus produced serves as the main reducing agent in the upper region of the furnace. 
the liquid iron runs downward to the bottom of the furnace and is with drawnthrough a tap hole. 
the lime stone which was added to the charged is known as flux.it decomposes to form CaO and carbon dioxide.CaO react with the gangue(mostly silica and some aluminia)to form their respective salts.they are known as slag. 
the slag floats as the moltan iron and is run off which molten iron is seen into sand moulds where it cools down to solid blocks called pig iron. 
q2) what is rusting? 
ans) rusting of iron:- when an iron is exposed to air and moisture its surface is gradually corroded and converted into a brown mass. this brown mass is known as rust. 
q3)how is rusting conrolled by the cathodic protection and electroplating? 
ans)cathodic protection:-to protect theironobject from corrosion by this method the object is counnected to a block of metal such as gine or aluminium which is comparitvely more reaction than iron when corrsion starts an electrochemical reaction takes place and only the more reaction prevented from rusting. 
electroplating:-electroplating is used to cover iron object chromium,nickel or other less easily corroded metals.this process used to prevent decorative as well as protective coatings. 
alloying:-rusting is often prevented by converting the iron into an alloy such as stainless steel. 
painting:- paint is generally used for coating large object such as ship,bridges and soon. 
grease and oil:- grease and oil is used for coating the moving parts of machinery. 
q4) how copper is extracted? 
ans)extraction of copper:- the extraction of copper from its ore involved concentration roasting,melting,reducing and electrical refining. 
1) concentration:-the ore is concentrated by a process known as froth floation.in froth floation the mixture of the mineral and impurities are mixed with water and oil.pure oil or creosote oil are usually used. air is blown into the mixture and the oil forms a froth which floats to the surface.the ore particles tend to get coated with oil and are carried to the surface with it.the froth along with the mineral particles is skimmen off from the top to get the concentrated. 
2) roasting:- the concentrated ore is roasted in a furnace.part of the sulphur is converted to sulphur dioxide and other impurities such as arsenic which are burnt off. 
3) smelting:-in the smelting process the roasted ore is mixed with sand and heated strongly until it melts.the remaining impurities react with the silica to form a slag of molten silicates.this is removed from the top of the molten mass which remain is called matte and consist of mixture of CuS2and FeS. 
4) reduction:-reduction of the matte is carried out in a converter where air is blown through.the molten material and molten material and molten copper is obtained. more sand is added as a flux to remove the iron in the form of an iron silicate slag. 
5) refining:- blistered copper is refined by electrolysis. blistered copper,in the anode and a plate of pure copper is made cathode. a solution of copper sulphate act as the electrolyte.the impure copper dissolves at the anode and is disposited in the form of pure coppe at the cathode. 
q5) write 3 chemical properties of copper? 
ans) chemical properties:- 
1) copper react with oxygen, sulphur and halogens under suitable condition to from the corresponding compound. 
2) it react with acid which contain oxygen,such as dilute nitric acid and concerned sulphuric acid. 
3) copper displace less reaction metal,such as silver andother precious metals like give and iron. 
 
<hr width="50%" />
 
chapter 10                   Carbon,silicon and nitrogen 
q1) what is allotrophy? describe cheif allotropic form of carbon. 
ans) allotrophy:- various form of the same element which have same chemical properties but different physical propertiesare called allotropic forma or allotropes and the phenomenon is called allotropy. 
allotropic forms of carbon:- 
1) diamond 
2) graphite 
1)diamond:-diamond is a transparent and bright.it is the hardest of all naturally occuring substances.it is used commercially for cutting glass,drilling rocks and ornamental purposes.it is a non conductor of heat and electricity. 
2)graphite:- it is greyish black and very soft.it is used in making lead pencles.graphite is a good conductor of electricity.it is not affacted by acids or alkalies.it is used as electrodes in many electrolytic processes. 
q2) describe the laboratory and industrial preparation ofcarbon dioxide.what is the action of carbon dioxide on: 
1)magnesium (2) carbon (3) lime water. 
ans) laboratory preparation of carbon dioxide:- it is prepared in the laboratory by the action of dilute acid on metal carbonates or bicarbonates. 
CaCO3+2HCl<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />CaCl2+CO2+H2O 
industrial preparation of carbon dioxide:- carbon dioxide is obtained on commercial scale by heating lime stone in a furnace. 
CaCO3<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />CaO+CO2 
carbon dioxide is also obtained as a by product during the production of alcohol from molasses by fermentation in the presence of yeast. 
C6H12O6<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2CO2+2C2H5OH 
1) action on megnesium:- highly reactive metals like magnesium continue to burn in presence of carbondioxide forming MgO. 
2Mg+CO2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2MgO+C 
2) action on carbon:-carbon dioxide is reduced to carbon monoxide when heated in presence of carbon which have sufficent chemical affinity for oxygen. 
C+CO2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2CO 
3) action on lime water:- when carbon dioxide ispassed through lime water it is turned milky due to the formation of calcium carbonate. 
Ca(OH)2+CO2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />CaCO3+H2O 
q3) what is glass?how is it manufactured?discuss types of glass with their usefulness? 
ans) glass:-glass is an inorganic super cooled liquid having no definite melting point and has high ricosity to prerent.its crystallization.glasses are formed by allowing molten silicate to cool. 
types of glass: 
1) ordinary window glass or soda glass:- it prepared by heating a mixture of silica sodium carbonates and calcium carbonate in a furnace. 
CaCO3+SiO2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />CaSiO3+CO2 
uses:- it is used in making bottles,windows and all kinds flat glass. 
2)borosilicate glass:- borosilicate glass is prepared from silica boronoxide,aluminuimoxide,and sodiumoxide.this glass is commonly known as pyrex. 
uses:-it is used for some kitchen and laboratory wares such as ovenware,beakers,flask and test tube. 
3) crystal glass:-crystal glass is made from silica lead oxide,potassium carbonate and calcuim carbonate. 
uses:- it is heavy glass which can be cut to give decorative glass ware. 
4) coloured glass:- glass can be prepared in different colours by the addition of small quantities of contain mettalic oxide or salt to molten glass. 
5) water glass and silica gel:- sodium silicate is known as water glass.it is prepared by heating a mixture of silica and sodium carbonate. 
Na2CO3+SiO2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />Na2SiO3+CO2 
uses:- water glass is used for various fire proofing materials. 
soda glass:-when an acid is added to a solution of water glass it turns into a jelly like state known by chemist as a gel. on dehydrating this gel by heatinh a hard porous materail is formed.this is called silica gel and it is used to absorb gases and vapour. 
6) fibre glass:-glass fibre is produced by dropping molten glass into a rotating refactory disc. the glass files off the disc forming fibre.glass fibre are mixed with plastic are used to mould car and boat bodies water tanks and sports good. 
q4) how can nitrogen be prepared in the laboratory?what is the action of N2 on:- 
1)CaC2 (2) H2 (3) Ca 
ans) laboratory preparation:- pure nitrogen is obtained in the laboratory by the following method. 
1) by heating a mixture of sodium nitrite and aqueous solution of ammonuim chloride. 
NH4Cl+NaNO3<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />NaCl+NH4NO2 
NH4NO2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />N2+2H2O 
2) by heating ammonuim dichromate. 
(NH4)2Cr2O7<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />Cr2O3+4H2O+N2 
3) by the fractional distrillation of air. 
niteogen can be obtained by the fractional distrillation of liquid air. air from which carbon dioxide has been removed is liquified by successive compression and expansion at low temperature. 
upon distrillation nitrogen gas is evolved first at-196c and thus seperated from oxygen. 
1)action on CaC2:- calcuim cyanamide is obtained by passing nitrogen over red hot calcuim carbide. 
CaC2+N2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />CaCN2+C 
2) action on H2:-if a mixture of hydrogen and nitrogen is heated at 400-450c in the presence of iron oxide and aluminuim sulphate under 200 atmospheric pressure it is converted to ammonia. 
N2+3H2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2NH3 
3) action on calcuim:-calcium is converted to calcuim nitrides when heated in a current of nitrogen. 
3Ca+N2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />Ca3N2 
q5) describe haber process for the manufacture of ammonia. 
ans) this is the most important synthethic method for a large scale preparation of ammonia. a mixture of pure nitrogen and hydrogen in the proportion of 1:3 by volume is compressed to 200 atmospheric pressure and then passed over iron oxide and alumminuim sulphate as catalyst(iron containing a little molybdenum) at 400-450c million of tons of ammonia are prepared annually by this method. 
N2+3H2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2NH3 
q6) how is nitric acid manufactyred from ammonia by ostward method?what is the action of HNO3 on: 
1) CuO (2) Cu (3) Mg 
ans) nitric acid is obtained on a large scale by the oxidation of ammonia.if a mixture of ammonia and air is heated up to 600c in the presence of platinum nitric oxide if produced. 
4NH3+5O2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />4NO+6H2O 
this an exothermic process and large amount of heat is evolved for this reason the chemical process continue and nitric oxide is converted to nitrogen peroxide in the presence of excess air. 
nitrogen peroxide formed above react with water to from nitric acid. 
3NO2+2H2O<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2NHO3+NO 
1) action on CuO:- when copper oxide is reacted with nitric acid it produced copper nitrate and water. 
CuO+2NHO3<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />Cu(NO3)2+H2O 
2)action on copper: when copper is rweacted with dilute nitric acid it produced copper nitrate ,nitric acid and water. 
3Cu+8HNO3<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />3Cu(NO3)2+4H2O+2NO 
3) action on Mg: when Mg react with nitric acid it produced magnesium nitrate and hydrogen gas is evolved. 
Mg+2HNO3<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" /> Mg(NO)3+H2 
 
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chapter 11                       Oxygen,sulphur and chlorine 
q1) how is oxygen industrially prepared from air and water? 
ans) industrial preparation: oxygen is obtained on an industrial scale from air and water. 
1) from air:- 
(a) air is a mixture of oxygen and nitrogen the ratio by volume being 21:78. the air is liquified by cooling under pressure and the liquid ait fractionally distilled.nitrogen being more volatile(boiling point-196c) escapes out first and oxygen being less volatile (boiling point -183) is left behind. 
(b) oxygen can also be obtained from air by a chemical method. barium oxide is heated upto 500c in air which combine with the oxygen of air and is converted into barium peroxide. barium peroxide on heating at 1000c decompose into oxygen and barium oxide. 
2BaO+O2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2BaO2 
2) from water:-oxygen is obtained on large scale by electrolysis of water. 
2H2O<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2H2+O2 
q2) what is action of O2 on:- 
1) C (2) Ca (3) Al 
ans) reaction with non metal:- non metal such as carbon,sulphur,phosphorus burn in oxygen forming their respestive oxides.hydrogen burns violently with oxygen to form water. 
C+O2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />CO2 
2) reaction with metal:-highly reactive metals such as sodium and potassium react rapidly with oxygen at low temperature. 
2Na+O2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2Na2O 
3)reaction with aluminium:- aluminuim powder burns violently in oxygen.flash bulbs used in photography contain aluminium foil in an atmosphere of oxygen. 
2Al+3O2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2Al2O3 
q3) what are oxides?discuss various type of oxide give their characteristic properties. 
ans) oxides:-the binary compounds of the element  with oxygen are called oxides. 
on the basic of valence number of oxygen they are ordinarily classified into four main groups,namely:- 
1) normal oxide 
2) peroxide 
3) super oxide 
4) suboxide 
1)normal oxides:- there are the oxides in which the valence number of oxygen is -2. 
normal oxide are classified into four types. 
a) basic oxide:- these oxide react with acid to produced salt and water. 
b) acidic oxide:- these oxide react with base to from salt and water. 
c) nuetral oxide:- these oxide are neither acid or a base their have no action on blue or red litmus. 
d) amphoteric oxide:-these are oxide which passess the properties of an acid as well as a base. 
2) peroxide:-the valence number of oxygen  in peroxide is -1.peroxide form hydrogen peroxide on reaction with dilute acid. example of peroxide are sodium peroxide,barium peroxide and hydrogen peroxide. 
3) superoxides:- the valence number of oxygen in super oxide in -1/2. superoxide have an excess amount of oxygen than normal and superoxides. 
4) suboxide:- suboxide have less quantity of oxygen than the normal oxides,they are unstable and very few suboxide are known. an example of suboxide is C3O2 which is named as carbon suboxide. 
q4) how is ozone produced? discuss the usefulness of protective layer of ozone and its deplation 
ans)ozone:-ozone,wich has a molecular formula O3, is an allotropic from of oxygen when an electrical discharge passes through ordinary diatomic oxygen energy is absorbed and some of oxygen is converted to ozone. 
3O2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2O3 
due to the presnce of this extra oxygen ozone ozone is used for disinfecting water supplies and large summings pools the atomic oxygen kills any harmful bacteria present because of this property ozone is used to sterilise air in confined and crowded spacessuch as underground railway stations and slaughter houses. 
ozone also find applications as a bleching agent for oilswaxes starch and flour. the atomic oxygen it releases,bleaches the organic dyes present in these material by oxidizing them. 
q5) how is sulphur extracted by frasch process. 
ans) extraction of sulphur:- harmen frasch developed a method for extraction of sulphur. the basic principle of this method is that sulphur is method under ground and pumped up to the surface. the details of the method are describe below. 
a bore is made to the deposists of sulphur and three concontric pipes are sunk into the bore. the outermost pipe (20 cm diometre) is sunk up to the deposists and the most inner (10 cm diometre) is held a little above the surface of deposists. super heated wter at 170c under a pressure of 16 atom is pumped down the outermost pipe.this water melts the sulphur (m.p 113c) which collect in a pool at the bottom. hot compressed air is blown down the innermostpipe.it forms a foam of molten sulphur which arises through the amnular space between the inner most pipe and the next when this foam ofsulphur reaches the surface it is collected in big wooden basin. after sometimes air escapes and sulphur solidfies in huge blocks at the bottom of tanks.sulphur obtained by this process is 99.5 percent pure. 
q6) how is sulphur dioxide prepared in laboratory ? 
ans) laboratory preparation:- sulphur dioxide is prepared by heating copper turning with concentrated sulphuric acid in round bottomed flask fitted with delivery tube and the gas is collected by upward displacement of air. 
Cu+2H2SO4<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />CuSO4+2H2O+SO2 
q7) what is the reaction of sulphur dioxide on:- 
H2O, H2S,FeCl3 
ans) reaction with water:- when sulphur dioxide is dissolved in water it froms sulphurous acid which decompose into its constituent on heating. 
SO2+H2O<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />H2SO3 
oxidizing nature:- sulphur dioxide bahves as an oxidizing agent to wards hydrogen sulphide and carbon monoxide. 
2H2S+SO2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2H2O+3S 
reducing nature:-because of its tendency to remove oxygen in the pressence of water sulphur dioxide acts as a strong reducing agent. 
2FeCl3+SO2+H2O<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />H2SO4+2FeCl2+2H2 
q8) how is sulphuric acid manufacted? 
ans) contact process:- now a day sulphuric acid is mostly manufacted by contact process. 
sulphur or iron pyrite is burnt in a regular supply of air to produce sulphur dioxide. 
S+O2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />SO2 
4FeS2+11O2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" /> 2Fe2O3+8SO4 
the resulting sulphur dioxide along with excess of air is purified from dust particles and arsenious oxide by passing gases through a dust chember in to whch steam is injected.the solid particles of impurities form droplet of water with steam and settle down.the moist gases are then dried by passing through a drying tower on which concentrated sulphuric acid is sprayed.arsenious oxide is then removed by passing the gases through a chamber provider with shelves packed with freshly prepared ferric chloride. 
after the removal of dust and other impurities the gases are passed through a contact chamber packed with plantinished asbestos or vomaduim pentoxide. the chamber is heated upto 450c where sulphur dioxide and air combine to form sulphur trioxide. 
2SO2+O2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2SO3 
sulphur trioxide thus obtained is absorbed in 97 percent sulphuric acid flovuing down a tower.the oleum or pyrosulphuric acid thus produced is diluted in tanks with a calculated amount of water in order to get 100 percent pure sulphuric acid. 
SO3+H2SO4<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />H2S2O2 
H2S2O2+H2O<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />2H2SO4 
q9) give laboratory and industrial preparation of chlorine? 
ans) laboratory preparation:- chlorine is usually prepared in the laboratory by the oxidation of hydrochloric acid. concentrated hydrochloric acid and magnaese dioxide are heated slowly in a round bottom flask. 
on heating greenish yellow chlorine gas comes out which is collected by the upward displacement of air.it is poisonous gas and hence on efficient ventilation of the leboratory is necessary. 
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MnO2+4HCl<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />MnCl2+2H2O+Cl2 
industrial preparation:- the chlorine gas is obtained on a large scale by the electrolysis of an aqueous solution of sodium chloride. chlorine is collected at the anode and sodium hydroxide is produced in the cell around the cathode. 
NaCl+H2O<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />Cl2+H2+2NaOH 
q10)what is the action of chlorine on:- 
1) CH4 (2) CO (3) NH3 
ans) reaction with hydrocarbons:- chlorine reacts with hydrocarbons in chain reaction to giveCCl4 and HCl 
CH4+4Cl2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />CCl4+4HCl 
reaction with carbon monoxide :- chlorine react with carbon monoxide to give phosgene. 
CO+Cl2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />COCl2 
reaction with non metal:-non metal like iron and tin combine with chlorine on heating. 
Sn+2Cl2<img height="15" src="http://www.apniweb.com/secondary/imageECS.JPG" width="77" />SnCl4 
 
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chapter 12                     An introduction of organic chemistry 
q1) difference between organic compound and inorganic compound. 
ans)                             organic compound                                           inorganic compound 
<table border="1" cols="2" style="width: 100%px;"><tbody>
<tr><td>1) carbon is essential constituent of organic compound.</td><td>1) presence of carbon is not essential but it is present in carbonates, bicarbonates and cynamids.</td></tr>
<tr><td>2) carbon and hydrogen are involved in their preparation.</td><td>2) carbon and hydrogen may not even be present.</td></tr>
<tr><td>3) usually they decompose at high temperature in the simple compound.</td><td>3) usually they are stable at high temperature.</td></tr>
<tr><td>4) most organic compound readily catch fire.</td><td>4) most inorganic compound do not catch fire.</td></tr>
<tr><td>5) their melting and boiling point are low.</td><td>5) their melting and boiling point are usually high.</td></tr>
<tr><td>6) organic compound contain covalent bond .</td><td>6) ionic bond are frequently in inorganic compound.</td></tr>
<tr><td>7) their molecular mass is very high.</td><td>7) molecular mass are usually low.</td></tr>
<tr><td>8) these are usually soluble in organic solvant.</td><td>8) these are insoluble in inorganic solvant.</td></tr>
</tbody></table>
q2) write the structure of methane and its chemical properties? 
ans) methane structure:- the carbon atom has four electron in tis valence shell. in molecule of methane it shares these with four hydrogen atom forming four covalent bond. 
each of the four covalent bond consist of a shaired pairs of electron abviously these shared pair of electron are negatively charged so they tendto repel cach other and move as far as possible the maximum seperation of the bond is achieved in a regular tetrahedral structure with the carbon atom at the center and four hydrogen atom at the apice the angle between any two C-H bond is the same about 109.5c. 
chemical properties 
combustion:- methane is an important fuel and its most important chemical property is that it burns in air on oxygen with a non-luminous flame. the burning of methane in air or oxygen is an exothermic reaction during which carbondioxide water and heat energy are produced. 
reaction with helogens:- methane react with chlorine in presence of sunlight in such a way that the four hydrogen atom of methane are replaced one by one in a step wise manner. 
q3) write the process of fractional ditrillation of pertroleum? 
ans) various fraction are seperated according to the difference in their boiling points and put to various uses. this method is known as fractional distrillation and compries as evaporation and condensation. 
the pretroleum to be refined is first heated in a special furnacecalled pipe still about 371-426c. the presence in the pipe is so adusted as to avoid evaporation of the crude oil. the hot pretroleum from the pipe still then goses to bottom of a fractionating tower. here the pressure is released and the liquid vaporazies. the vapour go up the fractionating tower where hydrocarbon that have high boiling temperature range are easily condensed to liquid in the lower part of the tower the fraction like gasoline which lower boiling temperature range continue to move up the tower as vapours which are them led to condenser where they change to liquid state. 
q4) write difference between drugs and medicine and write important drugs and their abuses? 
ans) defination of drugs:- a drugs is defined as a substance which affect most of the physiological function of a man or an animal. 
definetion of medicine:- a medicine is defined as any drugs prescribed by a physisicn for the treatment of an ailment of a patient. 
important drugs and their abuses:- drugs (intoxicants) can be put into four groups. 
1) sleeming drugs:- the drugs like alcohol,barbitroat and trannquilizes are incleded in this group their continue use damages the will power and memory of a person continous use of alcohol can permenantly damage the heart,liver and brain. 
2) stimulants:- drugs like cocaine,nicotine,caffeine,amphetamine are inculded in this group. due to the use of such drugs the energy of the body begins to be used up rapidly their use increases the normal heart  beat and blood pressure. 
3) narcotics:- drugs like heroin codine and opium are inculded in this group the common action in these drugs on the nervous system is that it make it quite dull and brain control of bodies organs is lost. feeling of hunger is lost and one suffer from constipation. 
4) hallucinogens:- this includes charas, bhang and marijuana. in this case,the effect is so dengrous that the addict loses his balance of mind his nerves get so much weak that his loses all his thinking and the capacity of understanding. 
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CHEMistry 9th class complete book

CHEMISTRY NOTES FOR 9th SCIENCE CLASS CHAPTER 1 INTRODUC...