Chemistry Notes - Solid State and Solutions PDF

Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 1 NSS തെളിമ Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ®...

Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 1 NSS തെളിമ Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 2 NSS തെളിമ PLUS TWO CHEMISTRY Units 1. solid state 2. solutions 3. electro chemistry 4. chemical kinetics 5. surface chemistry 6. General principles and process of isolation of elements 7. p block elements 8. d and f block elements 9. co ordination compounds 10. halo alkanes and halo arenes 11. alcohols, phenols and ethers 12. aldehydes ketones and carboxylic acids 13. amines 14. bio molecules 15. polymers 16. chemistry in every day life Edited By FIROZ T ABDULLA, HSST Sel.Grade Chemistry PAC Member Thaliparamba Cluster, Kannur Dist Seethi sahib HSS Taliparamba PREMJITH K M, HSST Junior Chemistry PAC Member ,Mattannur Cluster,Kannur Dist. Sivapuram HSS Sivapuram  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 3 NSS തെളിമ 1.SOLID STATE Solids are substances having definite shape and definite volume. In solids, the particles are closely packed and the force of attraction between the particles is strong. 1. Classification of solids Based on structural features Crystalline solids Long range order of arrangement Sharp melting point and heat of fusion Anisotropic in nature (Physical properties are different in different directions) Eg : Quartz,Diamond Amorphous solids Short range order of arrangement No sharp melting point and heat of fusion Isotropic in nature(Physical properties are same in all directions) Eg :Plastic,Rubber Based on nature of particles Molecular solids Ex:- HCl, SO2 Ionic solids Ex:-NaCl, MgO Metallic solids Ex:-Fe, Cu, Ag Covalent solids Ex:-SiO2,C (diamond), 2.Crystal lattice The regular three dimensional arrangements of constituent particles of a crystal in space is called crystal lattice or space lattice. 3.Unit cell A unit cell is the smallest repeating unit of a crystal lattice. 4.Types of unit cell Primitive Unit Cells: Here the constituent particles are present only at the corners of the unit cell. Centred Unit Cells: Here the constituent particles are present at the corners and other positions of the unit cell. These are of three types: i. Body-centred unit cells: Here the constituent particles are present at the body centre and at the corners of the unit cell. ii. Face-centred unit cells: Here the constituent particles are present at the centre of each faces and at the corners of the unit cell. iii. End-centred unit cells: Here the constituent particles are present at the centre of any two opposite faces and at the corners of the unit cell. 5.Number of atoms in different cubic unit cell Primitive (or simple cubic unit cell): 1(all particles are at the corners ,8 x 1/8=1) Body-centred cubic (bcc) unit cell: 2 (Particles at all the corners and at the centre, 8×1/8 +1=2) Face-centred cubic (fcc) unit cell:4 (Particles at all the corners and centre of each faces 8×1/8 +6×1/2 = 4)  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 4 NSS തെളിമ 6.Close packing in solids In solids the particles are closely packed. In close packed structures the particles are considered as hard spheres. 7.Packing Efficiency The percentage of the total space occupied by spheres (particles) is called packing efficiency. Volume occupied by all the spheres in the unit cell × 100 Packing Efficiency = Total volume of the unit cell Type of close packing Packing efficiency(%) fcc / ccp / hcp 74 bcc 68 primitive /simple cubic 52 8.Imperfections in solids (Crystal Defects) The deviation from the regular orderly arrangement of particles of a solid is termed as imperfections or crystal defects. The crystal defects are broadly classified into two – point defects: The imperfection around a point (an atom) in a crystalline substance line defects: The imperfection along a row Point defects are 3 types. a. Stoichiometric defect (Thermodynamic point defect): The defect which do not disturb the stoichiometry of solid. Two types of stoichiometric point defect shown by ionic solids are Schottky defect and Frenkel defect. Schottky Frenkel Due to the missing of equal number of Dislocation of cations from the lattice site to anions and cations from the lattice site. the interstitial site Density decreases Density remains same Cations and anions have similar size Ionic size difference is large Higher coordination number Lower coordination number Eg: NaCl, KCl, CsCl, AgBr Eg: ZnS, AgCl, AgBr, AgI b. Non stoichiometric point defect The defect which disturb the stoichiometry of the solid is called non-stoichiometric point defect (a) Metal excess defect due to anion vacancies: In this defect, the anion is missing from lattice site. To maintain electrical neutrality, electron is occupied in the anionic vacancies. This centre is called F-centre (Colour centre). Due to the formation of F-centre, the crystals become coloured. Examples:- Heating of NaCl in an atmosphere of Na develops yellow colour, ie, excess of Na in NaCl gives yellow colour, Similarly, Excess of K in KCI gives violet colour and excess of Li in LiCl gives pink colour.  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 5 NSS തെളിമ (b) Metal excess defect due to extra cation at interstitial site In this defect, extra cations are present at the interstitial site. To maintain electrical also present at the neighboring interstitial site. Examples:- When ZnO is heated, it loses oxygen and turns yellow in colour. Here excess Zn formed present at the interstitial site and equivalent number of electrons are also accommodated in the neighbouring interstitial site. (c) Metal deficiency defect due to cation vacancy In this defect, some cations are missing from lattice site. To maintain electrical neutrality an adjacent metal atom acquires extra positive charge. Examples:- FeO. FeO is mostly found with a composition of Fe.95O c. Impurity Defects: It is the defect arising due to the presence of foreign particles in a crystal. Eg. when molten NaCl is crystallised in presence of small amount of SrCl 2, some Na + ions are replaced by Sr ²+ ions and some cationic vacancies are formed. The no. of cationic vacancies produced is equal to the number of Sr ²+ ions occupied. Another example is a solid solution of CdCl 2 and AgCl 9.Properties of solids. Electrical properties: Conduction of Electricity in metals, semi-conductors and insulators - Band Theory According to band model, in metal there are two types of bands-valence band and conduction band. Valence band is the lower energy electron occupied band and conduction band is the higher energy unoccupied band. In metals, the valence band is either partially filled or it is overlapped with the conduction band. So electron can easily flow from the valence hand to the conduction band. In semi-conductors, there is a small energy gap between the valence band and conduction band and only a few electrons can enter into the conduction band. So they conduct only partially. In insulators, the gap between the valence band and the conduction band is large and so they do not conduct electricity. Magnetic properties of Solids a. Paramagnetic substance: The substance which is weakly attracted by magnetic field. Paramagnetism is due to the presence of unpaired electrons. It do not show magnetism in the absence of magnetic field. Example: O₂, Cu2+, Fe3+, Cr3+ b. Diamagnetic substance: The substance which is weakly repelled by magnetic field. Diamagnetism is due to the presene of paired electrons. Example:- NaCl, H ₂O, benzene c. Ferromagnetic substance:-The substance which is strongly attracted by magnetic field. It retains magnetism even in the absence of magnetic field. Ferromagnetism is due to the spontaneous alignment of magnetic moments (domains) in the same direction. Example:- Fe, Co, Ni, CrO₂, Gd (Gadolinium)  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 6 NSS തെളിമ d. Antiferromagnetic substance: The substance which are expected to have high magnetic moments but actually it possess zero magnetic moments. It is due to the alignments of magnetic moments in the opposite direction alternatively. Example:- MnO e. Ferrimagnetic substance: The substance which are expected to have high magnetism but actually it possess small magnetic moments.Here magnetic moments are cancelled each other. Example:- Fe3O4, (magnetite), ZnFe2O4, (Zinc ferrite), MgFe2O4, (Magnesium ferrite) 2. SOLUTIONS Solutions are homogeneous mixture of two or more substances. ➔ Solute:Substance in lesser quantity ➔ Solvent :Substance in higher quantity ➔ Solubility :Solubility of a substance is its maximum amount that can be dissolved in specific amount of solvent at a temperature. 1.Solubility of gas in liquid The solubility of a gas in a liquid depends pressure applied which is explained by Henry's law Henry's law: “As the pressure of gas increases solubility of gas in liquid also increases” Partial pressure (p) of the gas in vapour phase is proportional to the mole fraction (X) of the gas in the solution. ic. P=KHX (KH is Henry's constant) KH value is inversely proportional to solubility of a gas in a liquid Applications of Henry's law: (i) To increase the solubility of CO2 in soft drinks or soda. (i) Bends experienced by Scuba divers. (Medical condition created by solubility of nitrogen in the blood). To avoid bends, oxygen taken in oxygen cylinder is diluted with less soluble Helium (iii) Anoxia experinced by peoples at high altitude where the partial pressure of oxygen is less than the ground level. Effect of temperature the solubility of a gas in a liquid When temperature increases, the value of KH is increases. Therefore solubility of the gas in liquid decreases. Therefore aquatic life is more comfortable in cold water. 2.Vapour pressure of Liquid-Liquid solution Raoult's Law: For a solution of volatile liquids, the partial vapour pressure of each component in the solution is directly proportional to its molefraction. For component 1, P1∝X1 P1=P10X1 and for component 2, P2 ∝ X2 or P2 =P20 X2  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 7 NSS തെളിമ 3.Ideal solution: The solution which obeys Raoult's law are called ideal solutions. Here ∆H mix = 0 and ∆V mix = 0 For a binary solution contains two components A (solvent) and B (solute),A-A (solvent- solvent) and B-B(solute-solute) interactions are equal to the A-B (solvent-solute) interactions. Examples of ideal solution: (1) solution of n-hexane and n-heptane (2) solution of bromo ethane and chloro methane (3) benzene and toluene 4.Non ideal solution The solution which does not obey's Raoult's law are called ideal solutions. Here ∆H mix not equal to 0 and ∆V mix not equal to 0 The total vapour pressure of such solution is either higher or lower than predicted by Raoult's law. Therfore non ideal solution divided into two Non ideal solution showing Positive deviation from Roults law: The observed value of partial vapour pressure greater than that of theoretical value( A-B interaction less than A-A and B-B)(Change in volume and enthalpy will greater than zero) Eg:- Ethanol and acetone Non ideal solution showing Negative deviation from Roults law: The observed value of partial vapour pressure less than that of theoretical value( A-B interaction greater than A-A and B-B) (Change in volume and enthalpy will lower than zero) Eg: Chloroform and acetone Non ideal solution showing Non ideal solution showing Positive deviation Negative deviation 5.Azeotropic mixtures (Azeotropes) or Constant boiling mixture: They are binary mixtures having the same composition in liquid and vapour phase and boil at a constant temperature. For such solutions, it is not possible to separate the components by fractional distillation. They are two types- minimum boiling azeotrope The solutions which show a large positive deviation from Raoult’s law form minimum boiling azeotrope at a particular composition.  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 8 NSS തെളിമ maximum boiling azeotrope The solutions which show large negative deviation from Raoult’s law form maximum boiling azeotrope at a particular composition. 6.Colligative Properties Colligative property is the property which depend upon the number of solute particles and does not depend upon their nature. They are (1) Relative lowering of vapour pressure (2) Elevation of boiling point (3) Depression of freezing point (4) Osmotic pressure Applications of Colligative Properties Used to determine molar mass of non volatile solute (M₂) using the following equations 7.Osmosis and Osmotic Pressure,Reverse osmosis Osmosis :- It is the flow of solvent molecules from lower concentration side to a higher concentration side through a semi-permeable membrane Eg, for semi-permeable membrane are egg membrane, all animal and plant membrane, Cellulose acetate. Osmotic pressure :- It is defined as the excess pressure that must be applied on solution side to stop osmosis Reverse osmosis :- The direction of osmosis can be reversed if a pressure larger than osmotic pressure is applied to the solution side. Here solvent is flowing from lower concentration to higher concentration through semi permeable membrane. This process is called reverse osmosis. Reverse osmosis is used in desalination of sea water and in water purifiers. 8.Isotonic, Hypotonic & Hypertonic Solutions The solutions having same osmotic pressure at a temperature is called Isotonic solution Eg : blood and 0.9% (m/v)NaCl solution The solution having high osmotic pressure than other is called Hypertonic solution The solution having lower osmotic pressure than other is called Hypotonic solution  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 9 NSS തെളിമ 8.Importance of colligative properties (i) Osmotic pressure is used to measure molecular mass of proteins, polymers and other macromolecules because of two reasons: (a) osmotic pressure is measured at room temperature (b) molarity is used instead of molality. (ii) Anti freeze solutions (eg. Glycol) are used in automobile radiators to prevent the freezing of water (depression of freezing point). (iii) NaCl and CaCl2, is used to remove ice from road because it depress the freezing point of water. (iv) The osmotic pressure of fluid inside the blood cell and that of 0.9% (mass/volume) NaCI solution are equal , they are isotonic (solutions having same osmotic pressure). Therefore, 0.9%(mass/volume) NaCI solution is used in intravenous injections. 9.Abnormal molecular mass Molecular mass calculated on the basis of colligative properties may be lower or higher than the normal value. Such molecular mass is called abnormal molar mass. Abnormal molecular mass is due to the following reasons. (i) Dissociation of particles Due to dissociation of particles, the number of particles increases. Therefore colligative property increases, Hence molecular mass decreases Eg: KCI solution (Here KCI dissociated in to K and Cl-. Therefore number of particles increases.) (ii) Association of particles. Due to association of particles, the number particles decreases. Therefore colligative property decreases and hence molecular mass increases. Eg: Acetic acid (ethanoic acid) in benzene, ( In benzene, acetic acid dimerises due to hydrogen bonding. Therefore number of particles decreases). ➔ Van't Hoff factor i= Normal molecular mass Abnormal molecular mass For association i < 1 For dissociation i >1 3. ELECTRO CHEMISTRY It is a branch of chemistry that deals with the relationship between chemical energy and electrical energy and their inter conversions. 1.Daniel cell. It is constructed by dipping a Zn rod in ZnSO 4 solution and a Cu rod in CuSO 4 solution. The two solutions are connected externally by a metallic wire through a voltmeter and a switch and internally by a salt bridge. (i)Cu2+ + 2 e-→ Cu(s) (Reduction /In right half cell) (ii) Zn(s) → Zn2+ + 2 e- (Oxidation /In left half cell) Left half cell-Oxidation-Anode-Negative( LOAN) Right half cell-Reduction-Cathode-Positive. Here electron flow occurs from Zinc rod to Copper rod,and the conventional current flows from Copper rod to Zinc rod.  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 10 NSS തെളിമ 2. Electrode Potential(Eel) The tendency of a metal to lose or gain electron when it is in contact with its own solution is called electrode potential,(Eel). Electrode potential measured at standard conditions is known as Standard electrode potential(E0el). The cell potential is the difference between the electrode potentials (Reduction potentials) of the cathode and anode. Ecell = E cathode - E anode = E right - E left For Daniel cell, the symbolic cell representation is Zn(s)/Zn2+(aq)//Cu2+(aq)/Cu(s) 3. Measurement of Electrode Potential is done with the help of SHE/NHE. SHE can be represented as Pt(s)/H2(g)/H+(aq) when it acts as anode and as H+(aq)/H2(g)/Pt(s) when it acts as cathode. 4. Electrochemical series It is a series in which various electrodes are arranged in the increasing order of their Electrode Potential. Important applications of ECS are To compare the relative reactivity of metals. To predict the displacement reactions. To predict the liberation of H2 gas from mineral acids 5. Nernst equation –Various forms For a general electrode reaction M n+(aq) + ne– → M(s) Electrode potential Cell potential for Daniel cell Free energy and EMF of cell EMF of cell and Equilibrium constant 6.Variation of Molar conductivity ( Λm ) with concentration It is the conductivity of 1 mole of an electrolytic solution kept between two electrodes with unit area of cross section and at a distance of unit length. Molar conductivity decreases with the concentration of the electrolyte while conductivity increases with the concentration. For both strong and weak electrolyte, the molar conductivity increases with dilution (or decreases with increase in concentration) In case of weak electrolytes there is a sudden increase in molar conductivity during dilution where as in case of strong electrolyte a slight increase is observed When dilution reaches maximum or concentration approaches zero, the molar conductivity becomes maximum and it is called the limiting molar conductivity (Λm0).  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 11 NSS തെളിമ When dilution reaches maximum or concentration approaches zero, the molar conductivity becomes maximum and it is called the limiting molar conductivity (Λm0). For strong electrolytes, the relation between Λm and concentration can be given as: Λm = Λm0 - A√C (Debye Huckel Equation) Where ‘C’ is the concentration and A is a constant. The variation of Λm for strong and weak electrolytes is shown in the graphs For strong electrolytes, the value of ˄m0can be determined by the extrapolation of the graph. 7. Kohlrausch’s law The law states that the limiting molar conductivity of an electrolyte can be represented as the sum of the individual Molar ionic conductances of the anions and the cations of the electrolyte. Let the molar ionic conductances of anion and cation at infinite dilutions are λ + and λ – respectively,Then 0 0 0 Λm = υ+ λ+ + υ-λ- Where υ+and υ- represents the total number of cations and anions produced by one unit formula of an electrolyte. Applications Determination of ˄m0of weak electrolytes. By knowing the ˄m0 values of strong electrolytes, we can calculate ˄m0 of weak electrolytes. For e.g. we can determine the ˄m0of acetic acid (CH3COOH) by knowing the ˄m0 of CH3COONa, NaCl and HCl as follows: ˄m0(CH3COONa) +˄m0(HCl) - ˄m0(NaCl) = ˄m0 CH3COOH Determination of degree of dissociation of weak electrolytes By knowing the molar conductivity at a particular concentration (˄m) and limiting molar conductivity (˄m0), we can calculate the degree of dissociation (α) as, α = ˄m ˄m0 8.Faraday’s laws of electrolysis Faraday’s first law It states that the amount of substance deposited or liberated at the electrodes (m) is directly proportional to the quantity of electricity (Q) flowing through the electrolyte. Faraday’s second law It states that when same quantity of electricity is passed through solutions of different substances, the amount of substance deposited or liberated is directly proportional to their own equivalent masses. Products of electrolysis Electrolyte Product at Anode At cathode Aq.NaCl Chlorine Hydrogen Molten NaCl Chlorine Sodium  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 12 NSS തെളിമ 9. Batteries/ Commercial cells Non- rechargeable cells – Primary cell Drycell, Mercury cell Rechargeable cells – Secondary cells Lead storage cell,Ni-Cd cells. Cells Anode Cathode Electrolyte Overall cell reaction Dry Cell Zn Graphite Ammonium 2Zn(s) + MnO2 + NH4+→ (Leclanche container +MnO2 chloride 2Zn2+ + MnO(OH) + NH3 cell) (NH4Cl). Mercury cell Zinc – Paste of HgO Paste of KOH Zn(Hg) + HgO(s) → (Button cell) mercury and carbon and ZnO ZnO(s) + Hg(l ) amalgam Lead storage Lead Grid of lead 38% H2SO4 Pb(s)+PbO2(s)+2H2SO4(aq) cell packed with → 2PbSO4(s) + 2H2O(l) lead dioxide (PbO2) ✔ Mercury cell has a constant potential of 1.35 V since the overall reaction does not involve any ion in solution. Mercury cell is suitable for hearing aids, watches, etc. ✔ In Lead storage battery cell reaction can be reversed by passing current through it in the opposite direction. The most important secondary cell is, which is used in automobiles and inverters. 10. Fuel cells These are galvanic cells which convert the energy of combustion of fuels like hydrogen, methane, methanol,etc. directly into electrical energy. One example for fuel cell is Hydrogen – Oxygen fuel cell, which is used in the Apollo space programme. Here hydrogen and oxygen are bubbled through porous carbon electrodes into concentrated aqueous Sodium hydroxide solution. The electrode reactions are: Cathode: O2(g) + 2H2O(l ) + 4e–→4OH–(aq) Anode: 2H2 (g) + 4OH–(aq) → 4H2O(l) + 4e– Overall reaction is: 2H2(g) + O2(g) → 2 H2O(l ) Advantages The cell works continuously as long as the reactants are supplied. It has higher efficiency It is eco-friendly (i.e. pollution free) Water obtained from H2 – O2 fuel cell can be used for drinking. 11. Corrosion It is the slow destruction of the metal due to the attack of various atmospheric gases with the metallic surface.Some common examples are: The rusting of iron, tarnishing of silver, formation of green coating on copper and bronze (verdigris) etc. Rusting of iron is an electrochemical phenomenon. Chemically rust is hydrated ferric oxide (Fe2O3. x H2O)  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 13 NSS തെളിമ Methods to prevent corrosion Barrier protection By coating the metal surface with paint, varnish etc. Sacrificial protection By coating the metal surface with another electropositive metal like Zinc, Magnesium etc. The coating of metal with zinc is called Galvanisation and the resulting iron is called Galvanized iron. Anti-rust solutions. Cathodic protection. 4.CHEMICAL KINETICS 1.Rate of a chemical reaction The rate of a chemical reaction is the change in concentration of any one of the reactant or product in unit time. 2.Average rate and instantaneous rate a) Average rate The rate of a reaction at a particular interval of time is called Instantaneous Rate of a reaction. 2HI(g) → H2 (g) + I2 (g) rav = b)Instantaneous Rate of a reaction The rate of a reaction at a particular instant of time is called Instantaneous Rate of a reaction. For a general reaction, aA + bB → cC + dD, The instantaneous rate is given by 3. Factors affecting rate of a reaction 1. Concentration of the reactants 2. Temperature 3. Presence of catalyst 4.Dependence of rate of reaction on concentration: For a general reaction, aA + bB → cC + dD, Rate α [A]X[B]Y or r = k [A]X[B]Y (where x and y may or may not be equal to a and b) In the above equation ‘k’ is a constant called rate constant of the reaction 5.Rate law expression: The representation of rate of reaction in terms of molar concentration of reactants as experimentally determined is called rate law or rate equation or rate law expression. r = k[A]X [B]Y 6.Unit of Rate constant 1-n -1 (mol / L) s Where n is Order of reaction 7. Elementary and complex reactions A reaction that takes place in a single step is called elementary reaction. While a reaction that occurs in more than one step is called a complex reaction.  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 14 NSS തെളിമ 8. Order of reaction: It is the sum of powers of the concentration of the reactants in the rate law expression For a general reaction, aA + bB → cC + dD; r = k [A]X [B]Y, Order of the reaction = x + y Order of a reaction can be 0, 1, 2, 3 and even a fraction. 9. Examples for zero order reactions : A zero order reaction means that the rate of reaction is independent of the concentration of reactants. Some enzyme catalysed reactions Thermal decomposition of HI on gold surface Reactions which occur on metal surfaces. (The decomposition of gaseous ammonia on a hot platinum surface is a zero order reaction at high pressure.) 10. Examples for 1 st order reactions : Hydrogenation of ethene: C 2 H 4 (g) + H 2 (g) → C 2 H 6 (g); r = k[C 2 H 4 ] All natural and artificial radioactive decay 11.Pseudo First order reaction: Reactions which are not truly first order ,but become first order under special conditions are called pseudo unimolecular or pseudo first order reaction Inversion of cane sugar Ester hydrolysis 12. Molecularity of a reaction: It is the number of reacting species (molecules, atoms or ions) which must collide simultaneously in order to bring about a chemical reaction No Order Molecularity 1 It is the sum of the powers of the It is the total number of reactant species collide concentration terms in the rate law simultaneously in a chemical reaction expression 2 It is an experimental quantity It is a theoretical quantity 3 It can be zero or fractional It cannot be zero or fractional 4 It is applicable to both elementary and It is applicable only to elementary reactions complex reactions 13. Integrated rate equations  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 15 NSS തെളിമ 14.Graphical representation for zero and first order reaction 15. Half life of a reaction ( t 1/2 ) It is the time required for half of the reactant converted in to product Half life of a zero order reaction: Half life of a first order reaction: For zero order reaction t 1/2 ∝ [R]0. It is clear that t 1/2 for a zero order reaction is directly proportional to the initial concentration of the reactants and inversely proportional to the rate constant. For first order reaction t 1/2 is independent of initial concentration of reactant 16.Temperature Dependence of the Rate of a Reaction Reaction Arrhenius equation.This is an equation which relates rate constant with temperature A :Arrhenius Factor, Ea:Activation energy As temperature increases k increases thus rate of reaction also increases. For every 10°C rise in temperature, the rate of reaction becomes almost double. Expression for activation energy if different temperature and different rate constant are given below Ea = activation energy, k1 and k2 are the values of rate constants at temperatures T1 and T2 respectively.  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 16 NSS തെളിമ Activation energy (Ea): The energy requierd to form an activated complex Activation energy (E) = Threshold energy - Actual energy possessed by reacting molecules 17.Effect of Catalyst Catalyst provides an alternate path of lower activation energy to the reactant molecules. 18. Threshold energy: The minimum energy that the reacting molecules must posses in order to undergo effective collisions to form product is called threshold energy 5.SURFACE CHEMISTRY 1.ADSORPTION The presence of excess concentration of a molecular species at the surface rather than in the bulk of a surface is called adsorption. Types of Adsorption Physisorption Chemisorption 1. It arises because of van der Waals’ forces 1. It is caused by chemical bond between adsorbate and adsorbent. formation between adsorbate and adsorbent. 2. It is not specific in nature. 2. It is highly specific in nature. 3. It is reversible in nature. 3. It is irreversible 4. Enthalpy of adsorption is low 4. Enthalpy of adsorption is high Factors influencing adsorption of gases on solids. Nature of adsorbate: Surface area of adsorbent: Temperature:( The adsorption occurs readily at low temperature) Effect of Pressure- Adsorption Isotherms NOTE: Generally extend of adsorption of gases increases with increase in pressure. 1. Freundlich adsorption isotherm: The variation in of extent of adsorption (x/m) with pressure(P) at constant temperature can be expressed by means of a curve termed as adsorption isotherm. Freundlich adsorption isotherm: Mathematical exprssion is given as x/m= k.P1/n (n > 1) or log x/m = log k + 1/n log P For Adsorption from Solution Phase, x/m = kC1/n (C is the concentration)  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 17 NSS തെളിമ 2.Applications of Adsorption ➔ Production of high vacuum: ➔ Gas masks ➔ Control of humidity: ➔ Separation of inert gases: II.CATALYST Substances, which alter the rate of a chemical reaction without undergoing any chemical change is called catalyst, and the phenomenon is known as catalysis, divided into two groups: (a) Homogeneous catalysis (b) Heterogeneous catalysis The reactants and the catalyst are in the The reactants and the catalyst are in same phase different phases Eg: Oxidation of sulphur dioxide into sulphur Iron as catalyst in haber process for the trioxide with dioxygen in the presence of NO manufacture of ammonia. gas 3.Mechanism of heterogeneous catalysis Adsorption Theory:- (i)Diffusion of reactants to the surface of the catalyst. (ii) Adsorption of reactant molecules on the surface of the catalyst. (iii) Occurrence of chemical reaction on the catalyst’s surface through formation of an intermediate. (iv) Desorption of reaction products from the catalyst surface, and thereby, making the surface available again for more reaction to occur. (v) Diffusion of reaction products away from the catalyst’s surface. 4.Important features of solid catalysts are : 1.Activity :-ability to increase rate of a reaction 2.Selectivity:-ability to direct a reaction to yield a particular product selectively, 5.Shape- Selective Catalyst - Zeolites Zeolites are good shape-selective catalysts because of their honeycomb-like structures. They are microporous aluminosilicates with three dimensional network of silicates in which some silicon atoms are replaced by aluminium atoms giving Al–O–Si framework. Uses It converts alcohols directly into petrol Removal of permanent hardness. widely used as catalysts in petrochemical industries for cracking of hydrocarbons and isomerisation 6.Characteristics of enzyme catalysis Most highly efficient: Highly specific nature: Highly active under optimum temperature and PH  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 18 NSS തെളിമ III.COLLOIDS A colloid is intermediates of true solution and suspension with range of diameters of particle between 1 and 1000 nm. 7.Classification of colloids Based on Nature of attraction between Dispersed Phase and Dispersion Medium Lyophillic sols(solvent loving) Lyophobic sols(solvent hating) 1.There is much attraction existing between There is less attraction existing between Dispersed medium and Dispersed phase. Dispersed medium and Dispersed phase. Eg;starch sol Eg; Gold sol 2.Formed by simply mixing Dispersed medium Requires special methods. and Dispersed phase 3.Reversible sols. Irreversible sols. 4.Stable Unstable Based on Type of Particles of the Dispersed Phase (i) Multimolecular (ii) Macromolecular colloids: (iii)Associated colloids colloids: (Micelles): These are formed by the These type colloidal systems There are some substances association of atoms or contain macromolecules with which at low concentrations smaller molecules of particle size in colloidal behave as normal strong diameter < 1nm to form range. Examples are starch, electrolytes, but at higher species having size in the cellulose etc concentrations they exhibit colloidal range. colloidal behavior. For example, a gold sol. Eg: Soap solution 8.Preparation of Colloids Electrical disintegration or Bredig’s Arc method. Colloidal sols of metals such as gold, silver, platinum, etc., can be prepared by this method. In this method, electric arc is struck between electrodes of the metal immersed in the dispersion medium. Peptization Peptization may be defined as the process of converting a precipitate into colloidal sol by shaking it with dispersion medium in the presence of a small amount of electrolyte. 9. Purification of Colloidal Solutions : (i) Dialysis: (ii) Electro-dialysis: (iii) Ultrafiltration: It is a process of removing a Dialysis by applying Ultrafiltration is the dissolved substance from a an electric field is process of purification of colloidal solution by using a bag named electro dialysis. the colloid by using ultra made up of semi permeable filter paper. membrane.  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 19 NSS തെളിമ 10.Properties of colloids : Tyndall effect: When a strong beam of light is passed through colloid, the path of the path of the beam can be observed,termed as Tyndall effect. The Tyndall effect is due to the scattering of light by colloidal particles. Zsigmondy used Tyndall effect to set up an apparatus known as ultramicroscope. Brownian movement: Zig-zag motion of colloidal particles in the dispersion medium Charge on colloidal particles: Colloidal particles always carry an electric charge. Electrophoresis: The movement of colloidal particles towards anode or cathode under an applied electric potential Coagulation The process of settling of colloidal particles is called coagulation of the sol. When excess of an electrolyte is added to colloidal solution, negative ion causes the precipitation of positively charged sol and vice versa. 11.Hardy-Schulze rule. It has been observed that, generally, the greater the charge of the coagulating ion added, the greater is its power to cause coagulation.This is known as Hardy-Schulze rule. In the coagulation of a negative sol, the flocculating power is in the order: Al3+>Ba2+>Na+ Similarly, in the coagulation of a positive sol, the flocculating power is in the order: [Fe(CN)6]4– > PO4 3– > SO4 2– > Cl– 12.Protection of colloids Lyophilic colloids used for protecting Lyophobic sols from coagulation. 13.Emulsions : Colloids where both the Dispersion phase and Dispersion medium are liquids. There are two types of emulsions. Oil dispersed in water (O/W type) Water dispersed in oil (W/O type). Eg;Milk and vanishing cream Eg;butter ,cold cream,code liver oil Emulsifying agents : Proteins,gums Emulsifying agents : Long chain alcohols, lampblack, Applications of colloids Colloids are widely used in the industry. Following are some examples: Electrical precipitation of smoke: Purification of drinking water: Medicines: Most of the medicines are colloidal in nature. Tanning: Cleansing action of soaps and detergents:  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 20 NSS തെളിമ 6.GENERAL PRINCIPLES AND PROCESSES OF ISOLATION OF ELEMENTS 1.Minerals and Ores Minerals: Naturally occurring chemical substances in the earth’s crust obtained by mining. Ore : Out of many minerals only a few from which the metal is conveniently get extracted. For eg;Bauxite,china clay etc are minerals of Aluminium,but bauxite is selected as the ore. All the ores are minerals but all the minerals are not ores. Gangue: The impurities associated with the ores. 2.Metallurgy: The entire scientific and technological process used for isolation of the metal from its ores. The extraction and isolation of metals from ores involve the following major steps: Concentration / Benefaction of the ore, Extraction of the metal from its concentrated ore, and Purification / Refining of the metal. 1.CONCENTRATION / BENEFACTION OF THE ORE, Removal of the gangue from the ore. i) Hydraulic Washing (gravity separation or levigation) In such process a running stream of water is used to wash the powdered ore.The lighter gangue particles are washed away and the heavier ores are left behind. ii) Magnetic Separation If either the ore or the gangue is capable of being attracted by a magnetic field, then such separations are carried out (e.g., in case of iron ores). The powdered ore is carried on a conveyer belt which passes over a magnetic roller.The magnetic roller attracts the magnetic components and they are collected as a heap near that roller. The non magnetic components form a heap away from the impurities. iii) Froth Floatation Method This method has been in use for removing gangue from sulphide ores. In this process, a suspension of the powdered ore is made with water. To it pine oil is added.A blast of air is blown through the pipe of a rotating agitator. As a result, froth is formed which carries the ore to the surface(froth being lighter) and is skimmed off. It is then dried for recovery of the ore particles. iv)Leaching The process consists in treating the powdered ore with a suitable chemical reagent which can selectively dissolve the ore but not the impurities. Leaching of Alumina from bauxite Bauxite NaOH Sodium CO 2 Hydrated Heating Pure Alumina aluminate Al2O3  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 21 NSS തെളിമ Metal Ores Concentration methods Iron( Fe) Haematite,Magnetite, Siderite. Magnetic Separation Copper (Cu) Copper glans, Copper Pyrites Froth Floatation Method [ Malachite] Zinc (Zn) Zinc blende Froth Floatation Method [ Calamine] Aluminium (Al) Bauxite Leaching II. EXTRACTION OF THE METAL FROM ITS CONCENTRATED ORE Extraction from concentrated ore involves two major steps (a) conversion to oxide by calcination and roasting Calcination: Roasting: Heating the ore in limited supply of air. The ore is heated in excess supply of air at a This removes the volatile impurities temperature. and moisture and at the same time During roasting,impurities such as S,P,As decomposes any carbonate into oxide. etc are removed as their volatile oxides. ZnCO3(s) ZnO(s) + CO2(g) 2ZnS + 3O2 →2ZnO + 2SO2 (b) reduction of the oxide to metal. Extraction of iron from Haematite. (Using Blast furnace) Haematite(Fe2O3) is mixed with limestone(CaCO3) and Coke(C) are put into the blast furnace.Coke act as a fuel as well as reducing agent and limestone as flux. At 500 – 800 K (lower temperature range in the blast furnace)–the temperature is lower and the iron oxides (Fe2O3 and Fe3O4) coming from the top are reduced in steps to FeO. 3 Fe2O3 + CO → 2 Fe3O4 + CO2 Fe3O4 + 4 CO → 3Fe + 4 CO2 Fe2O3 + CO → 2FeO + CO2 At 900 – 1500 K (higher temperature range in the blast furnace): Coke burns in CO2 to form CO which reduces FeO to Fe C + CO2 → 2 CO FeO + CO → Fe + CO2 Limestone(flux) is also decomposed to CaO which removes silicate impurity of the ore as slag. The slag is in molten state and separates out from iron. CaCO3 + SiO2 → CaSiO3 (Slag) + CO2 Different types of Iron Pig iron Cast iron Wrought iron Iron coming out from Carbon content (about 3%) The purest form of commercial Blast furnace contains and is extremely hard and iron (with less than 0.08% about 4% carbon and brittle. carbon) It is soft,malleable many impurities and ductile.  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 22 NSS തെളിമ Extraction of Copper from Cuprous oxide. Most of the ores are sulphide and some may also contain iron. Exraction of Cu from Copper pyrites involves following steps. The sulphide ores are roasted/smelted to give oxides: 2Cu2S + 3O2 → 2Cu2O + 2SO2 The oxide can then be easily reduced to metallic copper using coke: Cu2O + C → 2 Cu + CO Extraction of Aluminium from Bauxite (Hall-Heroult process) Electrolyte :purified Alumina,Al2O3 is mixed with Crayolite,Na3AlF6 Role of Crayolite: which lowers the melting point of the mixture and brings conductivity. Cathode: iron tank lined inside with carbon. Anode:A number of carbon rods dipping in the molten electrolyte. The electrolytic reactions are: Al2O3 → 2Al3+ + 3 O2- At Cathode: Al3+ + 3e– →Al(l) At Anode: C(s) + O2–→CO(g) + 2e– ( C(s) + 2O2– →CO2(g) + 4e– ) Ellingham diagram It is the graphical representation of standard Gibbs free energy change for the formation of various oxides of elements ,ΔfG0 againstTemperature. Application:To understand the variation in the temperature requirement for thermal reductions and to predict which element will suit as the reducing agent for a given metal oxide. Any metal will reduce an oxide of another metal that lies above it in an Ellingham diagram. Ex: Al can reduce FeO, ZnO, Cu2O but Al can not reduce MgO at a temperature below 1350 0C. Above this temperature, Al can reduce MgO. III. PURIFICATION / REFINING OF THE METAL. Removal of impurities from the crude metal. Important Refining methods are, (i) Distillation This is very useful for low boiling metals like zinc and mercury. The impure metal is evaporated to obtain the pure metal as distillate. (ii)Liquation In this method a low melting metal like tin can be made to flow on a sloping surface. In this way it is separated from higher melting impurities. (iii)Electrolytic refining Copper is refined using an electrolytic method. Anodes are of impure copper and pure copper strips are taken as cathode. The electrolyte is acidified solution of copper sulphate and the net result of electrolysis is the transfer of copper in pure form from the anode to the cathode: Anode: Cu →Cu2+ + 2 e– Cathode: Cu2+ + 2e– →Cu (iv)Zone refining  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 23 NSS തെളിമ A circular mobile heater is fixed at one end of a rod of the impure metal. The molten zone moves along with the heater as it moves forward. During this time the pure metal crystallises out of the melt and the impurities pass on into the adjacent molten zone. The process is repeated several times and the heater is moved in the same direction. At one end, impurities get concentrated. This end is cut off. This method is very useful for producing semiconductor and other metals of very high purity, e.g., Ge, Si, B,Ga and In. (v)Vapour phase refining Mond Process for Refining Nickel: Van Arkel Method for Refining for Zirconium Step1 : Ni(s) + 4CO(g) → Ni(CO)4 (g) Step:1 Zr(s)+ 2I2 (g) → ZrI4(g) Step 2: Ni(CO)4(g) → Ni(s) + 4CO(g) Step 2: ZrI4(g) → Zr(s) + 2I2(g) 1800K Refining method Metals (a) Distillation Zn,Cd,Hg (Low boiling) (b) Liquation Sn,Bi,Pb (Low melting) (c) Electrolytic refining Cu,Zn (d)Mond Process Ni (e)Van Arkel Method Zr,Ti (f) Zone refining Ge,Si (Semi conductors) 7. P BLOCK ELEMENTS I.AMMONIA 1.Industrial Method of Preparation of Ammonia ( Haber process ) 3.On a large scale, ammonia is manufactured by Haber’s process. N 2 (g) + 3H 2 (g) → 2NH 3 (g);∆ f H = – 46.1 kJ /mol Accordance with Le-Chatelier’s principle, To increase the formation of ammonia, High pressure that is a pressure of 200 × 105 Pa (about 200atm Pressure), Low temperature a temperature of 700 K(optimum temp), use of a Catalyst such as iron oxide with small amounts of K2O and Al2O3 to increase the rate of attainment of equilibrium. 2.Structure of ammonia Triagonal pyramidal Structure It has three bond pairs and one lone pair of electrons 3.Properties  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 24 NSS തെളിമ 1.In the solid and liquid states, it is associated through hydrogen bonds that accounts for its higher melting and boiling points 2. Ammonia is a lewis base,the one pair of electrons is available for donation. Therefore, it acts as a Lewis base.The presence of a lone pair of electrons on the nitrogen atom of the ammonia molecule makes it as Lewis base. 3.It donates the electron pair to the metals and forms co-ordinate linkage with metal ions.Formation of such complex compounds helps in the detection of metal ions such as Cu2+ , Ag+ ,due to its characteristic colour 4.Why does NO2 dimerise ? NO2 contains odd number of valence electrons. It behaves as a typical odd molecule. On dimerisation, it is converted to stable N 2O4 molecule with even number of electrons. II.NITRIC ACID 5.Industrial Preparation of Nitric acid (Ostwald's process ) This method is based upon catalytic oxidation of NH 3 by atmospheric oxygen. NO thus formed combines with more oxygen to form NO2 which dissolves in water to form HNO3 and can be concentrated by distillation up to 68% by mass. Further concentration to 98% can be achieved by dehydration with concentrated H2SO4. 6.Structure of Nitric acid 7.Properties 1.Action with Metals:-Concentrated nitric acid is a strong oxidising agent and attacks most of metals except noble metals such as gold and platinum. Cu reacts with dilute HNO3 to give NO and with concentrated acid to give NO 2 3Cu + 8 HNO3 (dilute) → 3Cu(NO 3 )2 + 2NO + 4H2O Cu + 4HNO3 (conc.) → Cu(NO 3 )2 + 2 NO2 + 2H2O Zn reacts with dilute HNO3 to give N2O and with concentrated acid to give NO2. 4Zn + 10HNO3 (dilute) → 4 Zn(NO 3 )2 + 5H2O + N2O  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 25 NSS തെളിമ Zn + 4HNO3 (conc.) → Zn (NO 3 )2 + 2H2O + 2NO2 2. Cr, Al do not dissolve in concentrated nitric acid because of the formation of a passive film of oxide on the Surface. 3..Concentrated nitric acid oxidises non–metals and their compounds. Iodine is oxidised to iodic acid, carbon to carbon dioxide,sulphur to H 2 SO 4 , and phosphorus to phosphoric acid. I 2 + HNO 3 → HIO3 + 10NO 2 +H 2 O C +HNO 3 → CO 2 + H 2 O + NO 2 S 8 + HNO 3 → H2SO4 + NO 2 + H 2 O P 4 + HNO 3 → H3PO 4 + NO2 + H 2 O 8.Brown Ring Test: Brown ring test is carried out by adding dilute ferrous sulphate solution to an aqueous solution containing nitrate ion, and then carefully adding concentrated sulphuric acid along the sides of the test tube. A brown ring [Fe (H2O) 5 (NO)] 2+ at the interface between the solution and sulphuric acid layers indicates the presence of nitrate ion in solution. NO 3- + 3Fe + 4H+ → NO + 3Fe + 2H 2 O 2+ 3+ Fe2+ + H2O → [ Fe ( H 2 O ) 6 ] 2 + 2+ [ Fe ( H 2 O ) 6 ] + NO → [Fe (H2O) 5 (NO)] 2+ + H 2 O (brown ring) The familiar brown ring test for nitrates depends on the ability of Fe 2+ to reduce nitrates to nitric oxide, which reacts with Fe2+ to form a brown coloured complex. 9.Phosphorus — Allotropic Forms White phosphorus Red phosphurus It is polymeric, consisting of discrete tetrahedral P4 molecule chains of P4 tetrahedra linked together 10.Phosphine PH3 In the laboratory, it is prepared by heating white phosphorus with concentrated NaOH solution in an inert atmosphere of CO2 P 3 + NaOH + 3H2O → PH 3 +NaHPO2 PH3 is basic in nature:- PH3 reacts with acids like HI to form PH4 I which shows that it is basic in nature. PH3 + HI → PH 4I PH3 is acting as a Lewis base Due to lone pair on phosphorus atom,  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 26 NSS തെളിമ III.PHOSPHORUS HALIDES Phosphorus forms two types of halides, PX 3 and PX 5 (X = F, Cl, Br). Phosphorus Trichloride 11.Preparation 1.It is obtained by passing dry chlorine over heated white phosphorus and also obtained by the action of thionyl chloride with white phosphorus. P 4 + 6Cl 2 → 4PCl 3 P 4 + 8 SOCl 2 → 4PCl 3 + 4SO 2 + 2S 2 Cl 2 12.Structure It has a pyramidal shape in which phosphorus is sp3 hybridised. 13.Properties Solution PCl 3 hydrolyses in the presence of moisture giving fumes of HCl. PCl 3 + 3H 2 O → H 3 PO 3 + 3HCl Phosphorus Pentachloride 14.Preparation 1.Phosphorus penta chloride is prepared by the reaction of white phosphorus with excess of dry chlorine. P 4 + Cl 2 → PCl 5 15.Structure In gaseous and liquid phases, it has a trigonal bipyramidal structure as shown. The three Equatorial P–Cl bonds are equivalent, while the two axial bonds are longer than equatorial bonds. This is due to the fact that the axial bond pairs suffer more repulsion as compared to equatorial bond pairs 16.Properties When heated, it sublimes but decomposes on stronger heating. PCl 5 → PCl 3 + Cl 2 17.Oxo acids of phosphurus H3PO2 hypophosphurus acid H3PO3 orthophosphurus acid H3PO4 orthophosphuric acid H4P2O7 pyrophosphoric acid 18.Sulphur — Allotropic Forms Rhombic sulphur (α-sulphur) Monoclinic sulphur (β-sulphur Both rhombic and monoclinic sulphur have S8 molecules. These S8 molecules are packed to give different crystal structures. The S8 ring in both the forms is puckered and has a crown shape.  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 27 NSS തെളിമ 19.Oxoacids of Sulphur Sulphur forms a number of oxoacids such as H2SO3 , Sulphurous acid H2SO4 , Sulphuric acid H2S2O7 , pyro sulphuric acid( oleum) H2S2O8 , peroxodisulphuric acid IV.SULPHURIC ACID Sulphuric acid is one of the most important industrial chemicals 20.Preparation by Contact Process Sulphuric acid is manufactured by the Contact Process which involves three steps: Burning of sulphur or sulphide ores in air to generate SO2. Conversion of SO2 to SO3 by the reaction with oxygen. 2SO2 ( g ) + O2 ( g ) → 2SO3 ( g ) ; ∆rH 0 = − 196.6 kJ/mol The reaction is exothermic, reversible and the forward reaction leads to a decrease in volume. Therefore, low temperature and high pressure are the favourable conditions for maximum yield. There for according to Le-chatlier’s principle low temperature 720 k high pressure of 2 bar Catalyst vanadium pent oxide V2O5 is used here Absorption of SO3 in H2SO4 to give Oleum (H2S2O7 ). SO3 + H2SO4 → H2S2O7 (Oleum) Dilution of oleum with water gives H2SO4 of the desired concentration H2S2O7 +H2O → H2SO4 (Oleum) 21.Properties 1. It dissolves in water with the evolution of a large quantity of heat. Hence, care must be taken while preparing sulphuric acid solution from concentrated sulphuric acid. The concentrated acid must be added slowly into water with constant Stirring. 2.Concentrated sulphuric acid is a strong dehydrating agent. Many wet gases can be dried by passing them through sulphuric acid,provided the gases do not react with the acid. 3. Sulphuric acid removes water from organic compounds; it is evident by its charring action on carbohydrates. C 12 H 22 O 11 +H 2 SO 4 → 12C + 11H 2O 4..Hot concentrated sulphuric acid is a moderately strong oxidising agent. Cu + 2 H 2 SO 4 (conc.) → CuSO 4 + SO 2 + 2H 2 O S + 2H 2 SO 4 (conc.) → 3SO2 + 2H 2 O C + 2H 2 SO 4 (conc.) → CO2 + 2 SO 2 + 2 H 2 O  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 28 NSS തെളിമ INTER HALOGEN COMPOUNDS When two different halogens react with each other, interhalogencompounds are formed. They can be assigned general compositions as XX’ , XX’3 , XX’5 and XX’7 where X is halogen of larger size and X’ of smaller size and X’ is more electronegative than X. As the ratio between radii of X and X’ increases, the number of atoms per molecule also increases. Thus, iodine (VII) fluoride should have maximum number of atoms as the ratio of radii between I and F should be maximum. That is why its formula is IF 7 (having maximum number of atoms). 22.Preparation The inter halogen compounds can be prepared by the direct Combination or by the action of halogen on lower inter halogen compounds. The product formed depends upon some specific conditions, For example, Examples ClF , ClF3 , BrF5 , IF7 23.Structure Their molecular structures are very interesting which can be explained on the basis of VSEPR theory The XX 3 compounds have the bent ‘T’shape, XX 5 compounds square pyramidal and IF7 has pentagonal bipyramidal structures 24.properties 1.. In general, inter halogen compounds are more reactive than halogens (except fluorine). This is because X–X′ bond in Inter halogens is weaker than X–X bond in halogens except F–F bond. 6. XENON-FLUORINE COMPOUNDS Xenon forms three binary fluorides, XeF 2 , XeF4 and XeF6 by the direct reaction of elements under appropriate experimental conditions. XeF2 , XeF4 , XeF6 Xe (g) + 2F 2 (g) → XeF 4 (s) Xe (g) + F 2 (g) →XeF 2 (s) (1:5 ratio) (xenon in excess) XeF4 (g) + 3O2F2 (g2) → XeF6 (s) +O2 Xe (g) + 3F 2 (g) → XeF 6 (s) (1:20 ratio) 25.Structure  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 29 NSS തെളിമ (a) Xenon fluorides The structures of the three xenon fluorides can be deduced from VSEPR and these are shown in Figure. XeF 2 and XeF 4 have linear and square planar structures respectively. XeF 6 has seven electron pairs (6 bonding pairs and one lone pair) and would, thus, have a distorted octahedral structure as found experimentally in the gas phase. (b) Xenon-oxygen fluorides Preparation of XeOF4and XeO2F 2 Partial hydrolysis Of XeF 6 XeF6 + H2 O → XeOF4 + 2 HF XeF6 + 2 H2O → XeO2F2 + 4HF (c) Xenon-oxides Preparation of XeO3 Hydrolysis of XeF 4 and XeF 6 XeF6 + 3 H2O → XeO3 + 6 HF XeO 3 is a colourless explosive solid and has a pyramidal molecular structure. XeOF4 is a colourless volatile liquid and has a square pyramidal molecular structure 8. d and f BLOCK ELEMENTS 1.Magnetic properties The magnetic moment of transition element is only determined by spin angular momentum, depending upon the number of unpaired electrons and is calculated by using the ‘spin-only’ formula, i.e., where n is the number of unpaired electrons , μ is the magnetic moment and unit is Bohr magneton (BM). For example ,Ti 3+ [Ar]B 4s0 3d1 One unpaired electron in d orbital So Root 1(1+2) = root 3 = 1.73 BM Calculate the magnetic moment of a divalent ion in aqueous solution if its atomic number is 25. For atomic number 25, electronic configuration is [Ar] 4s2 3d5 the divalent ion in aqueous solution will have configuration [Ar]4s0 3d5 d5 configuration (five unpaired electrons). The magnetic moment, μ is 2, Formation of Coloured Ions  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 30 NSS തെളിമ Colour of transition metal is due to d-d transition Ion with d0 and d10 are colourless or white because no unpaired electrons are available for excitation all other ions with d electrons 1 to 9 are having characteristic colour due to d-d transition 3.Complex Formation A few examples K4[Fe(CN)6 ] , K3[Fe(CN)6 ] , [Cu(NH3)4 ]SO4 and Fe(CO)5 Transition metals forms number of complex compounds. This is due to the comparatively a)smaller sizes of the metal ions, b)their high ionic charges and the c)availability of d orbitals for bond formation. 4.Catalytic properties Catalytic property of transition metals is due to their ability to adopt multiple oxidation states and to form complexes. Examples for Catalysis:- Vanadium(V) oxide in Contact Process, Finely divided iron in Haber’s Process, and Nickel in Catalytic Hydrogenation 5.Oxidation state... shows variable valency Transition elements show variable oxidation states because energies of ns sub level and (n-1)d sub level are almost equal.Highest oxidation state of transition metal is exhibited in its oxide or fluoride. Because of small size and high electronegativity, oxygen or fluorine can oxidise the metal to its highest oxidation state. 6.Hardness and Melting points Except Zn, Cd and Hg transition metals are hard and they have high melting point. The high melting points of these metals are attributed to involvement of greater number of unpaired electrons. Greater the number of unpaired electrons stronger will be metallic bonding and higher will be melting points. Among all transition elements W has highest melting point Zn, Cd and Hg do not contain unpaired electrons. Therefore, they are soft metals. 7.Alloy formation Transition elements form alloys due to similar size e.g. Manganese steel 8. Formation of interstitial compounds Transition metals forms interstitial compounds because small atoms like H, C or N are trapped inside the crystal lattices of transition metals. As a result they have high melting points than those of pure metals. They are very hard. Some important compounds of Transition elements  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 31 NSS തെളിമ 1.POTASSIUM DICHROMATE K2Cr2O7 9.Preparation Dichromates are generally prepared from chromate, which in turn are obtained by the fusion of chromite ore ( FeCr2O 4 ) with sodium or potassium carbonate in free access of air. The reaction with sodium carbonate occurs as follows: 4 FeCr2O4 + 8 Na2CO3 + 7O2 → 8 Na2CrO4 + 2 Fe2O3 + 8 CO2 The yellow solution of sodium chromate is filtered and acidified with sulphuric acid to give a solution from which orange sodium dichromate, Na 2Cr2O7.2H2O can be crystallised after cooling. 2Na2CrO4 + 2 H2SO4 → Na2Cr2O7 + Na2SO4+ H2O The solution of sodium dichromate Is treated with potassium chloride. Na2Cr2O7 + 2 KCl → K2Cr2O7 + 2 NaCl Orange crystals of potassium dichromate crystallise out. 10.Properties of Potassium dichromate K2Cr2O7 i) The chromates and dichromates are interconvertible in aqueous solution depending upon pH of the solution. 2 CrO42- (yellow) + 2H + → Cr 2O72- (orange) + H2O Cr 2O7 2- (orange) + 2 OH- → 2 CrO4 2- (yellow) + H2O ii) Oxidising action It acts as strong oxidizing agent in acidic medium K2Cr2O7 + H2SO4 → K2SO4 + Cr2(SO4)3 + H2O + 3[O] Therefore acidified K2Cr2O7 oxidises i)Potassium Iodide to Iodine K2CrO7 + H2SO4 + KI → K2SO4 + Cr2(SO4 )3 + H2O + I2 ii)Hydrogen Sulphide to sulphur K2Cr2O7 + H2SO4 + H2S → K2SO4 + Cr2(SO4) 3 + H2 O + S 11. Structures of chromate ion, and dichromate ion, CrO4 2- Cr2O7 2- 2. POTASSIUM PERMANGANATE KMnO4 12.Preparation Generally prepared From Pyrolusite ore ( MnO2) Step 1 Pyrolusite is fused with KOH in presence of air and an oxidizing Agent MnO2 + KOH + O2 → K2MnO4 +H2O Step 2 The dark green coloured Potassium manganate (K2MnO4 ) Disproportionate in acidic medium giving permanganate K2MnO 4 + H + → KMnO4 + MnO2 +H 2O The purple solution obtained on evaporation gives crystal of potassium permanganate Commercial method of preparation of Potassium permanganate  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 32 NSS തെളിമ Step 1 Pyrolusite is fused with KOH in presence of air and an oxidizing Agent MnO2 + KOH + O2 → K2MnO4 +H2O Step 2 Electrolytic oxidation of Potassium manganate gives potassium permanganate At anode, MnO 4 2- → MnO4- + e- At Cathode, 2H+ + e- → H2 Formed MnO 4 - reacts with K+ to form KMnO4 The purple solution obtained on evaporation gives crystal of potassium permanganate 13.Properties of Potassium Permanganate Oxidising action KMnO 4 acts as strong oxidizing agent in acidic medium KMnO 4 + H 2 SO 4 → K2 SO 4 + MnSO4 + H 2 0 + 5[O] Therefore acidified KMnO 4 oxidises Many compounds Acidified KMnO4 oxidises i)Ferrous ion to ferric ion KMnO 4 + H2SO4 + Fe 2+ → K 2SO 4 + MnSO4 + H2O + Fe 3+ ii)Hydrogen sulphide in to sulphur KMnO + H SO + H S → K SO + MnSO + H O +S 4 2 4 2 2 4 4 2 14.Structure of Manganate and permanganate ion 15. Lanthanoids Lanthanoids are 14 elements coming after Lanthanum starting from Lutetium and ends in Lawrencium.In lanthanide filling of electron takes place in 4f sub shell before 5d orbitals. It belongs to sixth period. General electronic configuration is ns2 (n-1)d 0,1 ( n-2) f 1 -14. The common oxidation state of lanthanoid is +3. Example La3+,Ce3+...... 16. Lanthanoid contraction --Atomic and ionic Radii Steady and slow decreasing of atomic and ionic radii of lanthanoids from La 3+ to Lu3+ is called as Lanthanoid contraction. Reason for lanthanoid contraction This is Because of ineffective shielding effect of 4f orbital due to its diffused shape, As a result , the shielding effect caused by one 4f electron by another is less than one d electrons by another with increasing nuclear charge along the series. As a result whole nuclear power reaches to outermost shell and size slowly decreases Consequence of lanthanoid contraction  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 33 NSS തെളിമ 1. The radii of some elements of second transition series is similar to third transition series Eg:- Zr and Hf , Nb and Ta 2. Lanthanoids occur together in nature and separation become difficult 17. Use of lanthanoids 1. Misch metal is alloy of lanthanoids (about 95% lanthanoids, about 5% iron and traces of S,C, Ca and Al). Misch Metal is used in Mg based alloy to produce bullets, shell etc. 2. Mixed oxides of lanthanoids are employed as catalysts in petroleum cracking. 9. CO-ORDINATION COMPOUNDS Ligands The ions or molecules bound to the central atom/ion in the coordination entity are called ligands. Unidentate:-When a ligand is bound to a metal ion through a single donor atom, the ligand is said to be unidentate. Example Cl– , H2O , NH3 etc.., Didentate :- When a ligand can bind through two donor atoms as in the ligand is said to be didentate Example H2NCH2CH2NH2 (ethane-1,2-diamine) or C2O4 2– (oxalate), Polydentate:-when several donor atoms are present in a single ligand the ligand is said to be polydentate. Example N(CH2CH2NH2)3, Note:- Ethylenediaminetetraacetate ion (EDTA4–) is an important hexadentate ligand. It can bind through two nitrogen and four oxygen atoms to a central metal ion. Nomenclature of Mono nuclear co-ordination compounds (IUPAC) Write the formulas for the following coordination compounds: (a) tetraammineaquachloridocobalt(III)chloride [Co(NH3 ) 4(H2O)Cl]Cl2 (b) potassiumtetrahydroxidozincate(II) K2 [Zn(OH)4 ] (c) potassiumtrioxalatoaluminate(III) K3 [Al(C2O4 ) 3 ] (d) dichloridobis(ethane-1,2-diamine)cobalt(III)ion [CoCl2 (en)2 ] + (e) tetracarbonylnickel(0) [Ni(CO)4 ] Write the IUPAC names of the following coordination compounds: (a) [Co( NH3)5Cl]Cl2 pentaamminechloridoocobalt(III)chloride (b) [Cr( H2O)6]Cl3 hexaaquachromium(III)chloride (c) K3[Fe(CN)6] potassiumhexacyanidoferrate(III) (d) [NiCO4] tetracarbonylnickel(0) 3+ (e) [Cr(en)3] tris(ethylene diamine)chromium(III) ion (f) [Pt(NH3 )2Cl(NO2 )] diamminechloridonitrito-N-platinum(II) (g) K3 [Cr(C2O4 )3 ] potassiumtrioxalatochromate(III) (h) [CoCl2 (en)2 ]Cl dichloridobis(ethane-1,2-diamine)cobalt(III)chloride (i) [Co(NH3 )5 (CO3 )]Cl pentaamminecarbonatocobalt(III)chloride (j) Hg[Co(SCN)4 ] mercurytetrathiocyanato-S-cobaltate(III)  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 34 NSS തെളിമ 2.Isomerism in coordination compounds:- Compounds which have same molecular formula,but different structures and therefore different physical and chemical properties are called isomers. Depending upon the position and arrangement of ligands around the central metal atom several types of isomerism are possible.Isomerism are broadly classified into two. A. Structural isomerism These are isomers which have different structural arrangement around the central metal atom. The various structural isomers are. a. Ionisation isomerism These type of isomerism arises because of the capability of coordination compounds to produce different ions in solution. Eg:- [Co(NH3)5Br]SO4 and [ Co(NH3)5SO4]Br b. Hydrate isomerism or solvate isomerism This type of isomerism arises because of the capability of water molecule to appear in a variety of ways inside and outside the coordination sphere. Eg:- Three hydrate isomerism are possible for the molecular formulae CrCl 3 6H2O Eg:- [ Cr(H2O) 6]Cl3 [ Cr(H2O)5Cl] Cl2.H2O [ Cr(H2O)4Cl2]Cl 2H2O c. Linkage isomerism : It is shown by the complex containing ambidentate ligand with more than one donor atom. Eg:- when NO2 - is bonded to the metal through nitrogen the ligand is named as nitrito-N and if it is bonded to the metal through oxygen ( ONO - ) the ligand is named as nitrito-O. Eg:- [Co(NH3)5 NO2]Cl2 and [Co(NH3)5 ONO]Cl2 - d. Coordination isomerism This type of isomerism arises from the interchange of ligands between cationic and anionic entities in the complex.. Eg:- [ Cu(NH3)4] [ PtCl4] and [ Pt(NH3)4] [ CuCl4] [ Co(NH3)6] [ Cr(CN)6] and [ Cr(NH3)6] [ Co(CN)6] B. Stereo isomerism Isomers are those which contain same atom or group but they differ in the spatial arrangement around the central atom. They are of two types. a.Geometrical isomerism Also known as cis-trans isomerism. These types of isomerism arises due to different spatial arrangements of ligands.. C.N 4 Square planar complex of formula [MX2L2 ] In a square planar complex of formula [MX2L2 ] (X and L are unidentate),Here the two identical ligands either occupy adjacent positions to each other(cis isomer) or opposite to each other (trans-isomer). C.N 6 Octahedral complexes of formula [MX 2L4 ] In octahedral complexes of formula [MX2L4 ] two ligands X may be oriented cis or trans to each other  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 35 NSS തെളിമ Complexes of formula [MX2 (L– L)2 ] This type of isomerism also arises when didentate ligands L – L [e.g., NH2 CH2 CH2 NH2 (en)] are present in complexes of formula [MX2 (L– L)2 ] Facial and Meridional isomerism [MA3B3 ] Ex [Co(NH3 )3 (NO2 )3 ]. If three donor atoms of the same ligands occupy adjacent positions at the corners of an octahedral face, we have the facial (fac) isomer. And if the positions are around the meridian of the octahedron, we get the meridional (mer) isomer b. Optical Isomerism Optical isomers which are mirror images to each other and cannot be superimposed on one another are called as enantiomers. Such molecules or ions that cannot be superimposed are called chiral. The enantiomer are called dextro (d) and laevo (l) depending upon the direction they rotate the plane of polarised light in a polarimeter (d rotates plane polarised light to the right direction , where as l to the left). Optical isomerism is common in octahedral complexes involving didentate ligands. In a coordination entity of the type [PtCl2 (en)2 ] 2+, only the cis-isomer shows optical activity Another Example [Co(en)3 ] 2+ Bonding in metal carbonyls(synergic bonding) Metal carbonyls are formed between metal and carbon monoxide ligands It posses both sigma and pi bond. Metal carbon sigma bond is formed by the donation of lone pair of electrons from carbonyl carbon in to vacant orbital of metal. The metal carbon pi bond is formed by the donation of a pair of electrons from the filled d orbital of metal in to vacant anti bonding orbital of carbon monoxide  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 36 NSS തെളിമ 10. HALO ALKANES AND HALO ARENES Halo alkanes or Alkyl halides are having general formulae R-X Example CH3 Cl , C2 H5 Cl Halo arenes or aryl halides having general formulae Ar X Example C6 H5 Cl HALO ALKANES 1. Methods of Preparation of Halo alkanes (i)From Alkenes by Addition of hydrogen halides: by reaction with HCl.HBr,HI Propene yields two products, however only one predominates as per Markovnikov’s rule. CH2 = CH2 HX CH3-CH2Cl (ii) From Alcohols ( R-OH ) Here the hydroxyl group of an alcohol is replaced by halogen.Many reactions are there 1. Thionyl chloride is preferred because in this reaction alkyl halide is formed along with gases SO2 and HCl which are in gaseous state and are escapable, R-OH + SOCl2 R-Cl + SO2 + HCl Other Examples R-OH(1 or 2 alcohol) + HCl an. ZnCl2 0 0 R-Cl+ H2O 0 R-OH (3 alcohol ) + HCl R-Cl+ H2O 3R-OH + PCl3 3 R-Cl + H3PO3 R-OH + PCl5 R-Cl + POCl3 + HCl (iii) By Halogen Exchange Reactions R-X + NaI R-I + NaX (where X = Cl, Br) ( Finkelstein reaction ) R-X + AgF R-F + AgX (where X = Cl or Br) ( Swarts reaction ) 2. Reactions of Halo alkanes (1) Nucleophilic substitution reactions The reaction in which a nucleophile replaces already existing nucleophile in a molecule is called nucleophilic substitution reaction. This reaction has been found to proceed by two different mechanism (a) Substitution nucleophilic bimolecular (SN 2 ) SN2 reaction occurs in one step. This mechanism proceeds through inversion of configuration, in the same way as an umbrella is turned inside out when caught in a strong wind. The reaction between methyl chloride CH 3Cl and hydroxide ion OH- to yield methanol CH3OH and chloride ion Cl- is example CH3 Cl + OH - CH 3 OH + Cl - Rate depends upon the concentration of both the reactants. So it follows second order kinetics.  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 37 NSS തെളിമ The order of reactivity of alkyl halides towards SN2 reaction Primary halide > Secondary halide > Tertiary halide Tertiary alkyl halide due to three bulky group shows greater sterric hindrance (b). Substitution nucleophilic unimolecular (SN1): SN1 reaction occurs in two steps. In the first step, the C—X bond undergoes slow cleavage to produce a carbo cation and a halide ion. In the second step, the carbo cation is attacked by the nucleophile to form the product. Here first step is the slowest and reversible. So it is the rate determining step. Since this step contains only one reactant, it follows first order kinetics. The reaction between tert- butyl bromide and hydroxide ion yields tert-butyl alcohol is example Rate of reaction depends upon the concentration of only one reactant, which is tert- butyl bromide ( 2- bromo-2-methyl propane ) so it follows first order kinetics step 1 step 2 The order of reactivity of alkyl halides towards SN1 reaction Tertiary halide > Secondary halide > Primary halide For a given alkyl group, the reactivity of the halide, R–I> R–Br>R–Cl>>R–F. 3. Enantiomers:- The stereo isomers related to each other as an object and non- super imposable mirror images are called enantiomers. Enantiomers possess identical physical properties namely, melting point, boiling point, refractive index, etc. They only differ with respect to the rotation of plane polarised light. If one of the enantiomer is dextro rotatory, the other will be laevo rotatory. Example butan -2-ol 4. Racemic mixture:-  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 38 NSS തെളിമ A mixture containing two enantiomers in equal proportions will have zero optical rotation, as the rotation due to one isomer will be cancelled by the rotation due to the other isomer( internal compensation). Such a mixture is known as racemic mixture or racemic modification. A racemic mixture is represented by prefixing dl or (±) before the name, for example (±) butan-2-ol. The process of conversion of enantiomer into a racemic mixture is known as racemisation. Example:- (+)Tert.butyl chloride undergo SN1 reaction mechanism to give a dl mixture or Racemic mixture. Therefore resultant product will be optically inactive because of internal compensation. 5. Inversion:- If nucleophilic substitution taking place by SN 2 mechanism inversion in configuration taking place. Here nucleophile attack from the opposite side of leaving group resulting in inversion in configuration as shown in the example (+) Methyl chloride undergo SN2 mechanism to give (-)Methyl alcohol. (+) Methyl chloride (-)Methyl alcohol. HALO ARENES 6.. Methods of Preparation of Halo arenes 1) From amines by Sandmeyer’s reaction: When an aromatic primary amine (like aniline) is treated with HCl and sodium nitrite (NaNO2) at cold condition an aromatic diazonium salt is formed. This reaction is called Diazotisation. When this diazonium salt is treated with HX in presence of cuprous halide (Cu2X2), we get a halo benzene. This reaction is called Sandmeyer’s reaction. For the preparation of iodo benzene, the diazonium salt is treated with potassium iodide (KI) 7. Important Electrophilic substitution reactions of Halo arenes are  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 39 NSS തെളിമ (i) Halogenation:-Halo :- alkanes react with chlorine in presence of anhydrous ferric chloride to form o-dichlorobenzene and p-dichlorobenzene. (ii) Nitration:-On nitration using Conc. HNO3 and Conc. H2SO4 (nitrating mixture), chlorobenzene gives o-nitro chloro benzene and p-nitro chlorobenzene in which later is major product (iii) Sulphonation:-On :- sulphonation using Conc. H2SO4, chloro benzene gives ortho chloro benzene sulphonic acid and para chloro benene sulphonic acid ( major product). (iv) Friedel-Crafts alkylation Chloro benzene when treated with methyl chloride (CH3-Cl) in presence of anhydrous AlCl3, we get p-chloro toluene as the major product and o-chloro toluene as minor product ( v) Friedel-Crafts acylation :-Chloro :- benzene when treated with acetyl chloride (CH3-CO-Cl) in presence of anhydrous AlCl3, we get p-chloro acetophenone as the major product an o-chloro acetopheneone as minor product 11. ALCOHOLS, PHENOLS, ETHERS Alcohol R-OH Phenol Ar OH Ether R-O-R ALCOHOLS R-OH 1. Nomenclature Methyl alcohol ( Methanol )... CH3OH Ethyl alcohol ( Ethanol )....C2H5OH 2.. Preparation of Alcohols From carbonyl compounds ( aldehydes,ketones and acids) (i) By reduction :- by the addition of hydrogen in the presence of catalysts such as platinum, palladium or nickel. R-CHO +H2 R-CH 2OH (ii) By using sodium borohydride (NaBH4 ) or lithium aluminium hydride (LiAlH 4 ). Aldehydes yield primary alcohols whereas ketones give secondary alcohols.  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 40 NSS തെളിമ R-CHO LiAlH 4/NaBH4 R-CH 2 OH ( 10 alcohol) R CO R LiAlH 4/NaBH4 R2 CH-OH ( 20 alcohol) (iii) By reduction of carboxylic acids and esters: Carboxylic acids are reduced to primary alcohols in excellent yields by lithium aluminium hydride, a strong reducing agent. LiAlH 4 R-COOH R-CH 2 OH Commercially, acids are reduced to alcohols by converting them to the esters, followed by their reduction using hydrogen in the presence of catalyst (catalytic hydrogenation). (iv) By using Grignard reagents Alcohols are produced by the reaction of Grignard reagents with aldehydes and ketones. Methanal ( formaldehyde) gives primary alcohol. Other aldehydes ( Eg :Ethanal (acetaldehyde) gives secondary alcohol and ketones gives tertiary alcohol H-CHO + RMgX R-CH 2 - OMgX H 2 O R-CH 2 -OH + MgX(OH) Formaldehyde adduct 1 0 alcohol R-CHO + RMgX R 2 CHOMgX H2O R 2 CHOH + MgX(OH) Aldehyde adduct 2 0 alcohol R 2 CO + RmgX R 3 COMgX H2O R 3 C-OH + MgX(OH) Ketone adduct 3 0 alcohol 3. Chemical Reactions of alcohols (i).Lucas Test:- This test is used to distinguish primary secondary and tertiary alcohols. Here alcohols react with hydrogen halides to form alkyl halides. Lucas reagent is a mixture of conc. HCl and anhydrous ZnCl 2. Tertiary alcohols react with Lucas reagent and form turbidity immediately; secondary alcohols form turbidity within 5 minutes while primary alcohols do not produce turbidity at room temperature. But they give turbidity on heating. ROH + HX → R–X + H 2 O (ii). Dehydration: Alcohols undergo dehydration (removal of a molecule of water) to form alkenes on treating with a protic acid or catalysts such as anhydrous zinc chloride or alumina. 4. Commercial Preparation of ethanol Ethanol (C2H5OH) It is obtained commercially by fermentation of  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 41 NSS തെളിമ sugars. yeast is added which provide the enzyme invertase and zymase.Slow Fermentation takes place in anaerobic conditions 5. Denaturation of alcohol. The commercial alcohol is made unfit for drinking by mixing in it some copper sulphate (to give it a colour) and pyridine (a foul smelling liquid). PHENOLS C6H5-OH 6. Nomenclature Hydroxy derivative of benzene is phenol. 7. Preparation of Phenols i) From halo arenes Chlorobenzene is fused with NaOH at 623K and 320 atmospheric pressure,then sodium phenoxide is formed which on acidification we get Phenol ii) From diazonium salts A diazonium salt is formed by treating an aromatic primary amine with nitrous acid (NaNO2 + HCl) at 273-278 K. Diazonium salts are hydrolysed to phenols by warming with water or by treating with dilute acids 8. Reactions of phenols a) Electrophilic aromatic substitution Common electrophilic aromatic substitution reactions taking place in phenol are i) Nitration with dilute nitric acid at low temperature (298 K), phenol yields a mixture of ortho and para nitrophenols.The ortho and para isomers can be separated by steam distillation. Nitrophenol is steam volatile due to intramolecular hydrogen bonding while p-nitrophenol is less volatile due to intermolecular hydrogen bonding which causes the association of molecules.  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 42 NSS തെളിമ ii) With concentrated nitric acid, phenol is converted to 2,4,6-trinitro phenol. ( picric acid). b) Kolbe’s reaction phenol with sodium hydroxide gives sodium phenoxide which undergoes electrophilic substitution with carbon dioxide, Ortho hydroxybenzoic acid is formed as the main reaction product. c) Reimer-Tiemann reaction phenol on treatment with chloroform in the presence of sodium hydroxide, a –CHO group is introduced at ortho position This intermediate on hydroysis produces salicylaldehyde. ETHERS R-O-R 9.Nomenclature IUPAC CH 3 O C 2H 5 Ethylmethyl ether Methoxyethane CH 3 O CH 3 Dimethyl ether Methoxymethane C 2 H 5 O C 2H 5 Diethyl ether Ethoxyethane C 6 H 5 O CH 2CH 3 Ethyl phenyl ether Ethoxybenzene 10. Preparation of Ethers Williamson synthesis It is an important laboratory method for the preparation of symmetrical and unsymmetrical ethers. In this method, an alkyl halide is allowed to react with sodium alkoxide. CH3X + CH3ONa CH3-O-CH3 + NaX CH3-CH2-Br + CH3-ONa CH3-CH2-O-CH3 + NaBr 11. Reactions of Ethers Electrophilic substitution (i) Halogenation: anisole undergoes bromination with bromine in ethanoic acid 12. ALDEHYDES, KETONES AND CARBOXYLIC ACIDS ALDEHYDES AND KETONES 1.Nomenclature  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 43 NSS തെളിമ HCHO Formaldehyde Methanal CH 3 CHO Acetaldehyde Ethanal CH 3 CO CH3 Acetone Propanone 2.Preparation of Aldehydes and Ketones By oxidation of alcohols: with mild oxidising agents like CrO3 [O] Primary alcohols give aldehydes R-CH2OH R-CHO [O] secondary alcohols give ketones. R2CHOH R2CO By dehydrogenation of alcohols: with Cu or Silver catalyst at 573K, Cu/573 K Primary alcohols give aldehydes R-CH2OH R-CHO Cu/573 K secondary alcohols give ketones. R2CHOH R2CO By ozonolysis of alkenes: Alkenes add ozone followed by hydrolysis with zinc dust and water, we get aldehydes or ketones. 3. Preparation of Aldehydes Rosenmund reduction. Acid chlorides react with hydrogen in presence of Pd supported on BaSO4, we get aldehydes. Stephen reaction.:-Nitriles are reduced to corresponding imine with stannous chloride in the presence of hydrochloric acid, which on hydrolysis give corresponding aldehyde. Etard reaction. Chromyl chloride oxidises methyl group to a chromium complex, which on hydrolysis gives corresponding benzaldehyde By Gatterman – Koch reaction:-When benzene or its derivative is treated with carbon monoxide and hydrogen chloride in the presence of anhydrous aluminium chloride or cuprous chloride, it gives benzaldehyde or substituted benzaldehyde. 4. Preparation of Ketones From acyl chlorides:-Treatment of acyl chlorides with dialkylcadmium gives ketones.  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® 44 NSS തെളിമ From nitriles :-Treating a nitrile with Grignard reagent followed by hydrolysis yields a ketone. Friedel-Crafts acylation reaction.:-When benzene or substituted benzene is treated with acid chloride in the presence of anhydrous aluminium chloride,gives corresponding ketone. 5. Chemical Reactions of Aldehydes and Ketones a).Reduction (i) Reduction to alcohols: Aldehydes and ketones are reduced to primary and secondary alcohols respectively by sodium borohydride (NaBH 4 ) or lithium aluminium hydride (LiAlH 4 ) as well as by catalytic hydrogenation R-CHO [H] R-CH2OH [H] R2CO R2CHOH b)Reduction to hydrocarbons: i) Clemmensen reduction The carbonyl group of aldehydes and ketones is reduced to CH 2 group on treatment with zinc- amalgam and concentrated hydrochloric acid ii).Wolff-Kishner reduction with hydrazine followed by heating with sodium or potassium hydroxide in high boiling solvent such as ethylene glycol. c)Oxidation Aldehydes are easily oxidised to carboxylic acids on treatment with common oxidising agents like nitric acid, potassium permanganate, potassium dichromate, etc. Even mild oxidising agents, mainly Tollens’ reagent and Fehlings’ reagent also oxidise aldehydes. R-CHO [O] R-COOH CH3-CHO [O] CH3-COOH Ketones are generally oxidised under vigorous conditions, i.e., strong oxidising agents and at elevated temperatures.  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ?