Category: Samacheer Kalvi Notes

Tamilnadu Samacheer Kalvi 12th Commerce Notes Chapter 21 The Sale of Goods Act, 1930 Notes

→ Sale of Goods is one of the most important Acts coming under special contract. This Act was passed in the year 1930.

→ Contract of sale of goods is a contract whereby the seller transfers or agrees to transfer the property (ownership) of the goods to the buyer for a price.

→ Mere possession of the goods does not entitle a person to ownership.

→ Buyer has unlimited rights of the property purchased against the whole world.

→ Essential Elements of a Contract of Sale: (1) Two Parties (2) Transfer of Property (3) Goods (4) Price (5) Includes both‘Sale’and‘Agreement to Sell’.

→ The term goods mean every kind of movable property other than actionable claim and money.

→ *Goods may be divided into existing goods, future goods and contingent goods.

→ Existing goods are those owned or possessed by the seller at the time of contract of sale.

→ Existing goods may again be divided into specific goods, ascertained goods and generic or unascertained goods.

→ Specific goods denote goods identified and agreed upon at the time of contract of sale.

→ The term ‘ascertained goods’ is also used as similar in meaning to specific goods. But this term may even refer to goods which become ascertained subsequent to the formation of the contract.

→ Unascertained or generic goods are those which are not identified and agreed upon at the time of contract of sale.

→ Future goods are those which a seller does not possess at the time of contract of sale but which will be manufactured or produced or acquired by him after entering into the contract of sale agreement.

→ Contingent goods are the goods, the acquisition of which by the seller depends upon a contingency (an event which may or may not happen). Contingent goods are a part of future goods.

→ A stipulation in a contract of sale with reference to goods may be a condition or a warranty.

→ Warranty represents a stipulation which is collateral to the main purpose of the contract.

→ In every contract of sale, there are certain expressed and implied conditions and warranties.

→ In the case of sale, seller has a right to sell the goods.

→ In a contract of sale by description, there is an implied condition that goods supplied should agree with the descriptions made by the seller.

→ Where goods are sold by showing samples by the seller e.g. foodgrains, cloth, medicine, chemicals etc., the bulk of goods supplied by the seller should be similar to the sample shown by the seller.

→ If goods are bought by description and the seller is a dealer in goods of that description, the implied condition is that goods must be of merchantable quality.

→ In the case of eatables, the goods must be wholesome besides being merchantable.

→ An implied condition as to quality or fitness for a particular purpose can also be fixed by the usage of trade.

→ There is an implied warranty that the buyer shall have and enjoy quiet possession of the goods.

→ The goods bought must not have been subject to any charge or right in favour of a third party.

→ Where the seller knows that the goods he is selling are dangerous or likely to be dangerous to the buyer and the buyer is ignorant of the danger, the seller should warn the buyer of the probable danger, otherwise he will be liable to compensate the buyer in case of any injury.

→ A seller is deemed to be an unpaid seller (a) when the whole of the price has not been paid or (b) a bill of exchange or other negotiable instrument given to him has been dishonoured.

→ Rights of an unpaid seller against the goods: (a) Right of Lien (b) Right of Stoppage in Transit (c) Right of Resale

→ Rights of an unpaid seller if the goods does not pass to the buyer: (i) Suit for price (ii) Suit for Damages (iii) Suit for Cancellation of the Contract (iv) Suit for Interest

Samacheer Kalvi 12th Commerce Notes

Tamilnadu Samacheer Kalvi 12th Commerce Notes Chapter 20 Liberalization, Privatization and Globalization Notes

→ India agreed to the conditions of World Bank and IMF and announced New Economic Policy (NEP) which consists of wide range of economic reforms. This new set of economic reforms is commonly known as the LPG or Liberalisation, Privatisation and Globalisation.

→ There are three dimensions of New Economic Policy. They are explained below: Liberalization Privatization, Globalization.

→ Liberalization refers to laws or rules being liberalized, or relaxed, by a government.

→ The government of India has adopted several measures of liberalization. They are:
(i) Liberalization for industrial licensing
(ii) Freedom for expansion and production to industries
(iii) Increase in the investment limit of the small industries
(iv) Foreign Exchange reforms
(v) Liberalization of export and import transactions

→ Privatization is the incidence or process of transferring ownership of a business enterprise, agency or public service from the government to the private sector.

→ Forms of Privatization:
(i) Contraction (minimisation) of public sectors
(ii) Sales of shares of public sectors to the private sector
(iii) Memorandum of Understanding
(iv) Disinvestment in PSUs

→ Globalisation means the interaction and integration of the domestic economy with the rest of the world with regard to foreign investment, trade, production and financial matters.

→ Forms of Globalization: (i) Foreign trade policy (ii) Export promotion (iii) Freedom to repatriate (iv) Reduction in tariffs (v) Encouraging open competition:

→ Highlights of the LPG [Liberalisation, Privatisation and Globalisation Policy]:
(i) Introduction of new Foreign Trade Agreements
(ii) Foreign Investment (FDI and FII)
(iii) MRTP Act, 1969 (Amended)
(iv) Deregulation
(v) Opportunities for overseas trade
(vi) Steps to regulate inflation
(v/i) Tax reforms
(viii) Abolition of License

Samacheer Kalvi 12th Commerce Notes

Tamilnadu Samacheer Kalvi 11th Chemistry Notes Chapter 1 Basic Concepts of Chemistry and Chemical Calculations Notes

Chemistry – Chemistry is the science which deals with all kinds of matter occurring on this Earth and in the outside universe.

Importance of Chemistry – Chemistry is the centre of life. It finds numerous applications in everyday life and it is indispensible for modem civilization.

Matter – It is anything which has mass and occupies space.

Physical classification of matter – They are solids, liquids and gases.

Chemical classification of matter – (i) Pure substances such as elements and compounds (ii) mixture such as homogenous and heterogeneous (iii) Inorganic compounds and organic compounds.

Plasma state – Gaseous state of matter at very high temperature containing gaseous ions and free electron is referred to as the Plasma state.

Atom – An atom is the ultimate smallest electrically neutral, being made up of fundamental
particles such as proton, neutron and electron.

Element – An element consists of only one type of atoms.

Classifications of elements – metals, non-metals and metalloids.

Molecule – It is the smallest particle made up of one or more than one atom in a definite ratio having stable and independent existence.

Classification of molecule – (i) monoatomic molecule (Sodium and Copper) (ii) diatomic (H₂ and Cl₂) and (iii) polyatomic (O₃, P₄ and S₈).

Compound – A molecule which contains two or more atoms of different elements are called a compound molecule, e.g. H₂0 (Water) and C0₂ (Carbon dioxide).

Atomic mass – It is the mass of an atom of an element expressed as a number relative to the mass of one atom of hydrogen or oxygen or carbon.

amu – One atomic mass unit is equal to l/12th of the mass of an atom of C-12 isotope.

1amu= 1.66056 x 10^-24 gram.

Molecular mass – Molecular mass of a substance represents the number of times the molecule of that substance is heavier than 1/12th of the mass of an atom of C-12 isotope.
Molecular mass = 2 x Vapour density

Formula mass – The sum of the atomic masses of all the atoms in a formula unit of a substance is called formula mass.

Mole Concept – The mole is defined as the amount of a substance which contains 6.023 x 10²³ particles such as atoms, molecules or ions. Mole is represented by the letter “n”. Avogadro’s hypothesis – ‘Equal volume of all gases under the same conditions of temperature and pressure contain the same number of molecules’.

Avogadro number (N) – It is the number of atoms present in one mole of an element or number of molecules present in one mole of a compound. The value of Avogadro number (N) = 6.023 x 10²³.

Molar mass – The mass of one mole of any substance in gram is called molar mass.

Molar volume – : It is the volume occupied by one mole of a substance in the gaseous state at STP. It is equal to 2.24 x 10^-2m³ (22.4 L).

Equivalent mass – The equivalent mass of an element is defined as the number of parts of the acid which contains one 1.008 part by mass of replaceable hydron atom
Equivalent mass = \(\frac{\text { Molar mass of the acid }}{\text { Basicity }}\)

Equivalent mass – The equivalent mass of an element is defined as the number of parts of the mass of an element which combines with or displaces 1.008 parts of hydrogen or 8 parts of oxygen or 35.5 parts of chlorine.
\(\frac{\text { Atomic mass }}{\text { Valency }}\)

Equivalent mass of acid – It is defined as the number of parts by mass of the acid which contains 1.008 part by mass of replaceable hydrogen atom.

Equivalent mass of an acid = \(\frac{\text { Molar mass of the acid }}{\text { Basicity }}\)

Basicity – It is the number of replaceable hydrogen atoms present in a molecule of the acid.

Equivalent mass of a base – It is defined as the number of parts by mass of the base which contains one replaceable hydroxyl ion.
Equivalent mass ot a base = \(\)\frac{\text { Molar mass of the base }}{\text { Acidity }}\(\)

Acidity – It is the number of hydroxyl ions present in one mole of a base.

Equivalent mass of a salt – It is defined as the number of parts by mass of the salt that is produced by the neutralization of one equivalent of an acid by a base.
Equivalent mass of the salt = Molar mass of the salt

Equivalent mass of an oxidizing agent – It is defined as the number of parts by mass which can furnish 8 parts by mass of oxygen for oxidation.

Equivalent mass of a reducing agent – It is defined as the number of parts by mass of the reducing agent which is completely oxidised by 8 parts by mass of oxygen.

Empirical formula – It shows the ratio of number of atoms of different elements in one molecule of the compound.

Molecular formula – It shows the actual number of different types of atoms present in one molecule of the compound. Molecular formula = (Empirical formula)_n

Stoichiometry equation – It is a short scientific representation of a chemical reaction.

Limiting reagents – The reactant used up first in a reaction is called the limiting reagent.

Oxidation reaction – It is a process of adding of oxygen or removal of hydrogen.

Reduction reaction – It is a process of removal of oxygen or addition of hydrogen.

Electronic concept of oxidation and reduction – The reaction that involves loss of electrons is called an oxidation reaction and reaction that involves gain of electrons is called a reduction reaction.

OIL – Oxidation Is Loss of electrons.

RIG – Reduction Is Gain of electrons.

Oxidation number – It refers to the number of charges an atom would have in a molecule or an ionic compound if electrons were transferred completely.

Types of redox reactions – (i) Combination reactions (ii) Decomposition reactions (iii) Displacement reactions (iv) Disproportionation reactions (v) Competitive Electron transfer reactions.

Combination reactions – When two or more substances combine to form a single substance, the reactions are called combination reactions.
A + B → C

Decomposition reactions – The reaction in which a compound splits up into two or more simpler substances are called decomposition reaction.
AB → A + B

Displacement reactions – The reactions in which one ion or atom in a compound is replaced by an ion or atom of the other element are called displacement reactions.
AB + C → AC + B

Disproportionation reactions – The reactions in which an element undergoes simultaneously both oxidation and reduction are called as disproportionation reactions.

Competitive electron transfer reactions – These are the reactions in which redox reactions take place in different vessels and it is an indirect redox reaction. In this reaction, there is a competition for the release of electrons among different metals take place.

Methods of balancing of redox reactions – (i) Oxidation number method (ii) Ion-electron method.

Samacheer Kalvi 11th Chemistry Notes

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Tamilnadu Samacheer Kalvi 11th Commerce Notes Chapter 30 Performance of Contract Notes

→ When the party has done what he had undertaken to do, it is called actual performance.

→ When the party offers to perform his obligation, it is not accepted by the promisee. So, it is also called offer to performance or tender.

→ According to Para 2 of Section 40, the promisor may employ a competent person such as agent to perform the promise, if the contract is not formed on personal condition.

→ A contract which involves the use of personal skill or it is found on personal considerations, comes to an end if the promisor dies.

→ According to Section 41, if a promisee accepts the performance of the promise by a third person he cannot afterwards enforce it against the promisor.

→ Various legal provisions are laid down under Section 46 to 50 regarding the time, place and manner of performance of a contract.

→ Under Section 48, performance on a certain day: If the promise is to be performed on a certain day the promisor may undertake to perform it after the application by the promisee to that effect.

→ Promises which form consideration or part of consideration for each other are called ‘reciprocal promise’.

→ Where the two promises are said to be performed simultaneously, they are said to be mutual and concurrent.

→ If section 60’is attracted, the creditor shall have the discretion to apply such payment for any lawful debt which is due to him from the person making the payment.

Samacheer Kalvi 11th Commerce Notes

Tamilnadu Samacheer Kalvi 12th Commerce Notes Chapter 6 Money Market Notes

→ Money Market is a market for purely short-term funds.

→ It is the segment of financial markets where in financial instruments having maturities of less than one year are traded.

→ According to Crowther, ’’the money market is the collective name given to the various firms and institutions that deal in the various grades of near money”.

→ The RBI defines the money market as, “a market for short-term financial assets that are close substitutes for money facilitates the exchange of money for new financial claims in the primary market as also for financial claims, already issued, in the secondary market”.

→ A well-developed Money Market serves the following objectives:

1. Providing an equilibrium mechanism for ironing out short-term surplus and deficits.

2. Providing a focal point for Central Bank intervention for influencing liquidity in the company.

3. Providing access in uses to users of short-term money to meet their requirements at a reasonable price.

→ Generally, transactions take place through phone, i.e., oral communication. Relevant documents and written communications can be exchanged subsequently.

→ The components of a money market are the Central Bank, Commercial Banks, Non-Banking Financial Companies, Discount Houses and Acceptance House.

→ The Commercial Banks are the nerve centre of the whole money market. They serve as vital link between the Central Bank and the various segments of the money market.

→ There should be a large demand and supply of short-term funds.

→ The central bank keeps their cash reserves and provides them financial accommodation in difficulties by discounting their eligible securities.

→ A Treasury bill is nothing but a promissory note issued for a specified period stated therein. The Government promises to pay the specified amount mentioned therein to the bearer of the instrument on the due date.

→ The features of the Commercial Bills are- Drawer, Acceptor, Payee, Discounter, Endorser, Assessment, Maturity and Credit Rating.

→ The drawing and acceptance of indigenous bills are governed by native custom or usage of trade.

→ A market whereby the Government or gilt-edged securities can be bought and sold is called ‘Government Securities Market’.

→ Government securities are issued for the purposes of refunding the maturing securities, for advance refunding securities, which have not yet matured and for cash financing, i.e., raising fresh cash resources.

Samacheer Kalvi 12th Commerce Notes

Tamilnadu Samacheer Kalvi 11th Chemistry Notes Chapter 9 Solutions Notes

Solution – It is a homogeneous mixture of two or more substances consisting of atoms, ions or molecules.

Solvent – The compound that is present in large amount in a homogeneous mixture is called solvent.

Solute – The compound that is present in small amount in a homogeneous mixture is called solute.

Aqueous solution – If the water is used as the solvent the resultant solution is called an aqueous solution.

Non-aqueous solution – If solvent other than water is used, then the resultant solution is called non-aqueous solution.

Types and examples of solution

Molality (m) – It is defined as the number of moles of solute present in 1 kg of the solution.

Molarity (M) – It is defined as the number of moles of solute present in 1 L of the solution.

Normality (N) – It is defined as the number of gram equivalents of solute present in 1 L of the solution.

Formality (F) – It is defined as the number of formula weight of the solute present in 1 L of the solution.

Mole fraction – It is defined as the ratio of the number of moles of the component to the total number of moles of all components present in the solution.

Mass percentage – It is the ratio of percentage of the mass of the solute to the mass of solution in grams.

Volume percentage – It is the ratio of percentage of volume of the solute to the volume of the solution in ml.

Mass by volume – It is the ratio of percentage of mass of the solute in g to the volume of the solution in ml.

Parts per million (ppm) – One ppm is equivalent to 1 milligram of the component per litre of solution.

Standard solution – A standard solution is a solution whose concentration is accurately known.

Solubility of a substance – The solubility of a substance is defined as the amount of the solute that can be dissolved in lOOg of the solvent at a given temperature to form a saturated solution.

Factors influencing the solubility – (i) Nature of solute and solvent, effect of temperature, effect of pressure.

Henry’s law – This law states that “the partial pressure of the gas in vapour phase (vapour pressure of the solute) is directly proportional to the mole fraction (x) of the gaseous solute in the solution at low concentration.
P_Solute ∝ x _solute in solution (or) P_solute = K_H .x solute in solution.

KH – ft is the empirical constant with dimensions of pressure.

Evaporation – The process in which the liquid in converted to vapour.

Condensation – The process in which the vapour is converted to liquid.

Vapour pressure – It is defined as the pressure of vapour in equilibrium with its liquid at a given temperature.

Binary solution – The solution which contains only two components is called binary solution.

Raoult’s law – This law states that “in the case of a solution of volatile liquids, the partial pressure of each component (A & B) of the solution is directly proportional to its mole fraction.
P_A = K . X_A

Dalton’s law of partial pressure – This law states that the total pressure in a closed vessel will be equal to the sum of the partial pressures of the individual components.
p_Total = P_A + P_B

Ideal solution – It is a solution in which each component i.e., the solute as well as the solvent obeys the Raoult’s law over the entire range of concentration.

Non-ideal solutions – The solutions which do not obey Raoult’s law over the entire range of concentration are called non-ideal solution.

Factors responsible for deviation from Raoult’s law – Solute-solvent interaction, dissociation of solute, association of solute, temperature, pressure, concentration.

Colligative properties – The properties of the solution which do not depend on the chemical nature of the solute particles but depends only on the number of solute particles present in the solution are called colligative properties.

Relative lowering of vapour pressure – It is defined as the ratio of lowering of vapour pressure to vapour pressure of the solvent. Mathematically,

Relative lowering of vapour pressure = Moles fraction of solute

Boiling point – It is the temperature at which the vapour pressure of the solution becomes equal to the atmospheric pressure (1 atm).

Elevation of boiling point – ΔT_b – T_b – T⁰_b
ΔT_b = k_b . m where k_b = molal boiling point elevation constant.

k_b – Ebullioscopic constant
\(k_{b}=\frac{\mathrm{RT}_{b}^{2} \mathbf{M}_{\text {solvent }}}{\Delta \mathrm{H}_{\text {vaporisation }}}\)

Freezing point – It is defined as the temperature at which the solid and the liquid states of the substances have the same vapour pressure.

Depression in freezing point ΔT_f – ΔT_f = k_f. m where k_f = molal freezing point depression constant.

k_f – Cryoscopic constant.

Osmosis – It is a spontaneous process by which the solvent molecules pass through a semipermeable membrane from a solution of low concentration to a solution of higher concentration.

Osmotic pressure – The pressure that must be applied to the solution to stop the influx of the solvent (to stop osmosis) through a semipermeable membrane is called osmotic pressure.
π = CRT

Isotonic solutions – Two solutions having same osmotic pressure at a given temperature are called isotonic solutions.

Reverse osmosis (RO) – It can be defined as a process in which a solvent passes through a semipermeable membrane in the opposite direction of osmosis, when subjected to a hydrostatic pressure greater than the osmotic pressure.

van’t Hoff factor (i) – It is defined as the ratio of the actual molar mass to the abnormal molar mass of the solute.

α_dissociation = \(\frac{i-1}{n-1}\)

α_association = \(\frac{(1-i) n}{n-1}\)

Samacheer Kalvi 11th Chemistry Notes

Tamilnadu Samacheer Kalvi 11th Chemistry Notes Chapter 10 Chemical Bonding Notes

Chemical bonds – The interatomic forces which holds the constituent atoms/ions together in a molecule are called chemical bonds.

Kossel-Lewis approach – Elements other than noble gases, try to attain the completely filled electronic configuration by losing, gaining or sharing one or more electrons from their outer shell.

Octet rule – The atoms transfer or share electrons so that all atoms involved in chemical bonding obtain 8 electrons in their outer shell.

Covalent bond – This type of mutual sharing of one or more pairs of electrons between two combining or more pairs of electrons between two combining atoms results in the formation of a chemical bond called a covalent bond.

Formal charge – Formal charge of an atom in a molecule is the electrical charge difference between the valence electron in an isolated atom and the number of electrons assigned to that atom in the lewis structure.
Formal charge –
\(\mathrm{N}_{\mathrm{V}}-\left[\mathrm{N}_{l}+\frac{\mathrm{N}_{b}}{2}\right]\)

Ionic bond (or) electrovalent bond – The bond formed by the complete transfer of electrons leads to the formation of cation and an anion which are held together by the electrostatic attractive force.

Coordinate covalent bond – In the bond formation, one of the combining atoms donates a pair of electrons and these electrons are shared by both the combining atoms. These type of bonds are called coordinate covalent bond.

Bond length – The distance between the nuclei of the two covalently bonded atoms is called bond length.

Bond order – The number of bonds formed between the two bonded atoms in a molecule is called the bond order.

Bond angle – A fixed angle created by the directional nature of the two covalent bonds which is between the two bonds in a molecule is called bond angle.

Bond enthalpy – It is defined as the minimum amount of energy required to break one mole of a particular bond in the molecule in their gaseous state.

Resonance – The lewis structures which differ only in the position of bonding and lone pair of electrons are called resonance structures and this phenomenon is called resonance.

Dipole moment – µ = q x 2d, where q = charge, 2d= distance between the two charges.

Unit of dipole moment – Debye unit (D), 1 Debye = 3.336 x 10^-30 C m (C m = coulomb metre).

Non polar molecules – Molecules that have zero dipole moment are called non polar molecules. For example, H₂, O₂, F₂.

Polar molecules – Molecules that have dipole moment value are called polar molecules. For example, HF, HCl, NO, CO.

Electronegativity difference

If X_A – X_B = 1.7, the bond A – B has 50% ionic character
IF X_A -X_B > 1.7, the bond A – B > 50% ionic character
IF X_A – X_B < 1.7, the bond A – B < 50% ionic character

Polarisation – A distortion in the electron cloud of the anion and its electron density drift towards the cation which results in some sharing of the valence electrons between these ions. Thus, a partial covalent character is developed between them. This phenomenon is called polarisation.

Fajan’s rule – The extent of polarisation in an ionic compound is given by Fajan’s rule.

• To show greater covalent character, both the cation and anion should have high charge on them.
• The smaller cation and larger anion show greater covalent character due to the greater extent of polarisation.
• Cation having ns² np⁶ nd¹⁰ configuration show greater polarising power than the cations with ns2np(> configuration. Hence, they show great covalent character.

VSEPR theory – Valence Shell Electron Pair Repulsion Theory: It is useful in predicting the shape of the molecules.

The repulsive interaction between the electron pairs – lp – lp > lp – bp > bp – bp lp = long pair, bp = bond pair

Shapes of molecules predicted by VSEPR theory –

Sigma bond (σ) – When two atomic orbitals overlap linearly along the axis, the resultant bond is called a bond.

Pi bond (π) – When two atomic orbitals overlap sideways, the resultant covalent bond is called pi bond (n bond).

Hybridisation – It is a process of mixing of atomic orbitals of the same atom with comparable energy to form equal number of new equivalent orbitals with same energy.

Types of hybridisation with shape and examples

Bond order – It is the half difference of number of electrons present in bonding molecular orbitals and the number of electrons present in antibonding molecular orbitals.
Bond order = \(\frac{\mathrm{N}_{b}-\mathrm{N}_{a}}{2}\)

LCAO – Linear combination of atomic orbitals.

ψ bonding – ψ_A + ψ_B

ψ antibonding – ψ_A ψ_B

Metallic bonding – The forces that keep the atoms of the metal so closely in a metallic crystal constitute is known as metallic bond (or) electronic bond.

Samacheer Kalvi 11th Chemistry Notes

Tamilnadu Samacheer Kalvi 11th Chemistry Notes Chapter 11 Fundamentals of Organic Chemistry Notes

Organic chemistry – It is the study of compounds of carbon.

Catenation – The tendency of an atom to form a chain of bonds with the atoms of the same element is called catenation.

Functional group – It is an atom or a specific combination of bonded atoms that react in a irrespective of the organic molecule in which it is present.

Homologous series – A series of organic compounds each containing a characteristic functional group and the successive members differ from each other in a molecular formula by a CH2 group is called homologous series.

Alkanes – C_nH_{2n + 2}

Alkenes – C_nH_2n

Alkynes- C_nH_2n-2

IUPAC – International Union of Pure and Applied Chemistry.

Nuclear substituted aromatic compound – These are the compounds in which the functional group is directly attached to the benzene ring. These are derivatives of benzene.

Molecular formula of an organic compound – It is the simplest, least informative representation, showing the ratio of atoms present.

Structural formula of an organic compound – It is the formula that shows the way of atoms in a compound comiected to each other.

Molecular models – These are physical devices that are used for a better visualisation and perception of three dimensional shapes of organic molecules.

Three dimensional representation of organic molecule – The simplest convention is solid and dashed wedge formula in which 3-D image of a molecule can be perceived from two dimensional picture.

Fisher projection formula – This s a method of representing three dimensional structures in two dimension.

Saw horse projection formula – The bond between two carbon atoms is drawn diagonally and slightly elongated. The lower left hand carbon is considered lying towards the front and the upper right hand carbon is considered lying towards the back.

Newman projection formula – In this formula, the molecules are viewed from the front along the carbon-carbon bond axis.

Isomerism – It is a phenomenon in which two or more compounds with the same molecular formula but different structures and properties are there.

Isomers – Compounds exhibiting the isomerism are called isomers.

Constitutional isomers – These isomers have same molecular formula but differ in their bonding sequence.

Chain (or) nuclear (or) skeletal isomerism – These isomers differ in the way in which the carbon atoms are bonded to each other in a carbon chain.

Position isomerism – Compounds with the same molecular formula and carbon skeleton but differ in the position of substituent are said to exhibit position isomerism.

Functional isomerism – Different compounds having the same molecular formula but different functional groups are said to exhibit functional isomerism.

Metamerism – It is a special kind of structural isomerism arises due to the unequal distribution of carbon atoms on either side of the functional group or different alkyl groups attached to the either side of the same functional group and having the same molecular formula.

Tautomerism – It is a special type of functional isomerism in which a single compound exists in two readily interconvertible structures that differ markedly in the relative position of atleast one atomic nucleus, generally hydrogen.

Stereoisomerism – The phenomenon in which the isomers which have same bond connectivity but different arrangement of groups or atoms in space in known as stereoisomerism.

Geometrical isomerism – The phenomenon in which the stereoisomers which have different arrangement of groups or atoms around a rigid framework of double bonds.

Cis isomer – It is the one in which two similar groups are on the same side of the double bond.

Trans isomer – It is the one in which two similar groups are on the opposite side of the double bond.

Optical isomerism – Compounds having same physical and chemical property but differ only in the rotation of plane of the polarised light are known as optical isomers and the phenomenon is known as optical isomerism.

Dextro rotatory – The optical isomer which rotates the plane polarised light to the right or in clockwise direction is said to be dextro rotatory.

Leavo rotatory – The optical isomer which rotates the plane polarised light to the left or in . anti-clockwise direction is said to be leavo rotatory.

Enantiomers – The optical isomers which rotate the plane polarised light with equal angle but in opposite direction are known as enantiomers.

Chiral carbon – A carbon atom whose tetravalency is satisfied by four different substituents is called asymmetric carbon or chiral carbon.

Sublimation – The process in which the substances on heaving converted directly from solid to vapour without melting is known as sublimation.

Azeotropes – Compounds which are constant boiling mixtures.

Extraction – The process of removing a substance from its aqueous solution by shaking with a suitable organic solvent is termed extraction.

Chromatography – It is selective distribution of the mixture of organic substances between a stationary phase and a moving phase (or) chromatography is defined as a technique for the separation of a mixture brought about by differential movement of the individual compound through porous medium under the influence of moving solvent.

\(R_{f}=\frac{\text { Distance moved by the substance from base line }(X)}{\text { Distance moved by the solvent from base line }(Y)}\)

Samacheer Kalvi 11th Chemistry Notes

Tamilnadu Samacheer Kalvi 11th Chemistry Notes Chapter 12 Basic Concepts of Organic Reactions Notes

Organic reactions – Substrate is an organic molecule reacts with reagent, which may be an organic, inorganic or any agent like heat, photon etc that brings about the chemical change to form a product. This is known as organic reactions.

Mechanism of the reaction – The series of simple steps which collectively represent the chemical change, from substrate to product is called as the mechanism of the reaction.

Type of fission of a covalent bonds – (i) Homolytic fission, and (ii) Heterolytic fission.

Homolytic cleavage –

• Homolytic cleavage is the process in which a covalent bond breaks symmetrically in such way that each of the bonded atoms retains one electron.
• This type of cleavage occurs under high temperature or in the presence of UV-light.
• In such molecules, the cleavage of bonds results into free radicals.
• Free radicals are short lived and highly reactive species.

Free radical initiators – The type of reagents that promote homolytic cleavage in substrate are called as free radical initiators.

Examples for free radical initiators –

• Azobisisobutyronitrile (AIBN)
• Benzoyl peroxide

Heterolytic cleavage –

• Heterolytic cleavage is the process in which a covalent bond breaks unsymmetrically such that one of the bonded atoms retains the bonded pair of electrons.
• It results in the formation of a cation and an anion.

Carbocation – In a carbocation, the carbon atom bearing positive charge. It is sp² hybridised and hence it has a planar structure.

Carbanion – In a carbanion,, the carbon atom bearing negative charge. It is sp³ hybridised and hence it is pyramidal in shape.

Nucleophiles – Nucleophiles are reagents that has high affinity for electropositive centers. They possess an atom has an unshared pair of electrons. They are usually negatively charged ions or electron rich neutral molecules.

Nucleophilic reagents – Ammonia, amines, water, alcohols, ethers, hydrogen sulphide, thiols.

Electrophiles – Electrophiles are reagents that are attracted towards negative charge or electron rich center. They are either positively charged ions or electron deficient neutral molecules.

Electrophilic reagents – Carbon dioxide, Aluminium chloride, borontrifluoriuc and ferric chloride.

Electron movement in organic reactions – There are three types of electron movement,

1. Lone pair becomes a bonding pair.
2. Bonding pair becomes a lone pair.
3. a bond breaks and becomes another bond.

Electron displacement effects in covalent bonds – Electron displacement effects in covalent bonds occurs due to the presence of an atom or group of different electronegativity or under the influence of some outside attaching group. The electron displacements are categorized into, Inductive effects, Resonance effect, electromeric effect and hyper conjugation.

Inductive effect (I) – It is defined as the change in the polarization of a covalent bond due to the presence of adjacent bonded atoms or groups in the molecule.

+1 effect – Atoms or groups which lose electron towards a carbon atoms are said to have a +1 effect. Example, (CH₃)₃C-, (CH₃)₂CH-, CH₃-CH₂-, CH₃

-I effect – Atoms or groups which draw electrons away from a carbon atom one said to have a -I effect. Example, -NO₂, F^–, Cl^–, Br^–, I^– , -OH, C₆H₅–

Electromeric effect – The electromeric effect refers to the polarity produced in a multiple bonded compound when it is attacked by a reagent when a double or a triple bond is exposed to an attack by an electrophile the two n electrons which from the 7t bond are completely transferred to one atom or the other.

Resonance or mesomeric effect – Certain organic compounds can be represented by more than one structure and they differ only in the position of bonding and lone pair of electrons. Such structure are called resonance (or) canonical structure. This phenomenon is also called resonance effect.

Positive resonance effect – Those atoms or groups which lose electrons towards a carbon atom are said to have a + M or + R effect.

Example, -Cl, -Br, -I, -NH₂, -NR₂, -OH, -OCH₂

Negative resonance effect – Those atoms or groups which draw electrons away from a carbon atom are said to have a -M or -R effect.

Example:

Hyper conjugation – The delocalization of electron of a-bond is called as hyper conjugation.

Substitution reaction – In this reaction an atom or a group of atoms attached to a carbon atom is replaced by a new atom or a groups of atoms.

Addition reaction – It is a characteristic reaction of an unsaturated compound. In this reaction two molecules combine to give a single product.

Elimination reaction – In this reaction two substituents are eliminated from the molecule, and a new C-C double bond is formed between the carbon atoms to which the eliminated atoms\groups are previously attached.

Oxidation and reduction reactions – Most of the oxidation reaction of organic compounds involves gain of oxygen or loss of hydrogen. Reduction involves gain of hydrogen and loss of oxygen.

Functional group inter conversion – Organic synthesis involves functional group inter conversions. A particular functional group can be converted into other functional group by reacting it with suitable reagents.

Samacheer Kalvi 11th Chemistry Notes

Tamilnadu Samacheer Kalvi 11th Chemistry Notes Chapter 13 Hydrocarbons Notes

Alkenes – Alkenes are unsaturated hydrocarbons that contain carbon-carbon double bond. They are represented by the general formulae C_nH_2n where n stands for the number of carbon atoms in the molecule. Alkenes are also known as olefins.

Geometrical isomerism – It is a type of stereoisomerism and it is also called cis-trans isomerism or geometrical isomerism. Such type of isomerism results due to the restricted rotation of doubly bonded carbon atoms.

MarkovnikofFs rule – When an unsymmetrical alkene reacts with hydrogen halide, the hydrogen atom adds to the carbon that has more number of hydrogen atoms and halogen adds to the carbon atom having fewer hydrogen atoms.

Kharasch addition – Metal catalysed free radical addition of CXCl₃ compounds to alkenes is called Kharasch addition.

Polymerisation – A polymer is a large molecule formed by the combination of large number of small molecules. The process is known as polymerisation.

Alkynes – Alkynes are unsaturated hydrocarbons that contain carbon-carbon triple bond in their molecules. Their general molecular formula is C_nH_2n-2.

Ozonolysis – Ozone adds to carbon-carbon triple bond of alkynes to form ozonides. This process is known as ozonolysis.

Aromaticity – A compound may be aromatic, if it obey the following rules,
The molecule must be co-planar.
Complete delocalisation of π electrons in the ring.
Presence of (An + 2)π electrons in the ring, where n is an integer (n = 0,1,2 …). This is known as Huckel’s rule.

Ortho and para directing groups – OH, – NH₂, – NHR, – CH₃ – OCH₃ etc.

Meta directing groups NO₂, – CN, – CHO, – COOH etc.

Polynuclear aromatic hydrocarbons – Two or more benzene rings fused to form polynuclear aromatic hydrocarbons.

Samacheer Kalvi 11th Chemistry Notes