hsc chemistry preparation tips part - ii

12th

Chemistry

Preparation

Tips

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Unit No.

Unit Max. Marks

Marks with

Option

01 Solid State 4 6

02 Solutions and Colligative Properties 5 7

03 Chemical Thermodynamics and Energetics 6 8

04 Electrochemistry 5 7

05 Chemical Kinetics 4 6

06 General Principles and Processes of Isolation of Elements

3 5

07 P – Block Elements 8 10

Total 35 49

Chemistry Section – I

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Unit No.

Unit Max. Marks

Marks with

Option

08 d & f – Block Elements 5 6

09 Co-ordination Compounds 3 4

10 Halogen Derivatives of Alkanes ( & Arenes) 4 6

11 Alcohols, Phenols & Ethers 4 6

12 Aldehydes, Ketones & Carboxylic acids 5 7

13 Organic Compounds Containing Nitrogen 4 6

14 Biomolecules 4 6

15 Polymers 3 4

16 Chemistry in Everyday Life 3 4

Total 35 49

Chemistry Section – II

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Q – 1 ] Select and write most appropriate answer from the given

alternative for each sub – question. [ 7 ]

Q – 2 ] Answer any six [ out of eight ] of the following [ 12 ]

Q – 3 ] Answer any three [ out of four ] of the following [ 9 ]

Q – 4 ] Answer any one [ out of two ] of the following [ 7 ]

Paper Format for Section I & II [ 35 marks each ]

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1 – Mark Questions -

Definition / Statement / Objective Questions

2 – Mark Questions

Big structures of last two topics

Two step conversion, Polymerization processes

Difference - 4 points ( example No Mark ) / Distinguish by reaction

Short Notes, Salient Features of Theory ( 4 points )

Relation between ΔH & ΔU etc

Derivations / Laws of electrolysis

Structures of oxides of Nitrogen /

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2 – Mark Questions

Mfg. Processes ( Haber’s Process for ammonia/ Contact Process)

Allotropes of P or S

Oxy – acids of chlorine

Defects in crystal / limitations / Rault’s law / Diagrams

Resonating structures / Electronic Configurations

2 – point answers / Isomerism, Naming of co – ordination compounds

Numericals

3 – Mark QuestionsABC type crystal structures

Laws and Derivations

Daniel, Cell SHE, Calomel Electrode, Lead Accumulator

3 – point answers / Reaction mechanism / SN1, SN2, Optical activity

Multi step reactions ( balancing not required ) / Methods of preparation

Numericals - Calculations in same units throughout

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12th

Chemistry8 ] d - f Block

Elements

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d – Block Elements :- The atoms of the elements in which the last electron enters the d – orbital of penultimate ( last but one ) energy level are known as d – block elements. This indicates that in these elements, last two shells are incompletely filled.

Electronic Configuration of first ( 3d ) Transition Series ( 21 Sc – 30 Zn )

[ Ar ] 3d 1 – 10 4 s 1 – 2

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Oxidation States of first transition series

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Electronic configuration of lanthanides :-

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Lanthanide contraction : - Lanthanide contraction is a term used in chemistry to

describe different but closely related concepts associated with smaller than expected

atomic radii of the elements in the lanthanide series.

Definition :- The decrease in the atomic and ionic radii of the lanthanide elements

with increasing atomic number is known as lanthanide contraction. Thus, the first

element lanthanum has the largest, while the last element lutetium has the smallest

radius among these elements.

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12th

Chemistry9 ] Co - ordination

Compounds

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Isomerism in Coordination Compounds

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Stereoisomerism in metal complexes with coordination number 6.

Stereoisomerism in metal complexes with coordination number 6 ( octahedral complex ) of the type [ M a4 b2 ] n±

For example, consider a complex [ Cr ( NH3 ) 3 Cl 3 ]. The structures of cis and trans

isomers are



Structure of complex compounds based on valence bond theory

E ] Structure of Hexaamminecobalt (III) ion, [ CO ( NH3 ) 6 ] 3 +

1.Hexaamminecobalt ( III ) ion, [ CO ( NH3 ) 6 ] 3 + is a cationic complex, oxidation state of Co is +3 and CN = 6

Electronic configuration : 27Co [ Ar ] 3 d7 4 s2

Electronic configuration : Co 3 + [ Ar ] 3 d6 4s0 4p0

NH3 is a strong ligand, due to spin pairing effect, all the four unpaired electrons in

3d orbital are paired giving two vacant 3d orbitals.



The coordination number is 6, Co 3 + ion gets six vacant orbitals by hybridisation of two

3d vacant orbitals, one 4s and three 4p orbitals forming six d2sp3 hybrid orbitals giving

octahedral geometry. It is an inner complex.

6 lone pairs of electrons from 6NH3 ligands are

accommodated in the six vacant d2sp3 hybrid orbitals. The six hybrid orbitals of Co 3 + overlap with

filled orbitals of NH3 forming 6 coordinate bonds

giving octahedral geometry to the complex.



Geometry of complex : Hexaamminecobalt ( III ) ion has a octahedral geometry due

to d2sp3 hybridisation.

Magnetic property : Hexaamminecobalt ( III ) ion has no unpaired electrons. Hence

the complex is diamagnetic. (Magnetic moment, μ = 0 )

Effect of ligands : Ammonia ligands causes 3d electrons to be shifted to 3d – orbitals

so that all the ten electrons are paired up in 3d – orbitals.

12th Chemistry

10 ] Halogen

Derivatives

11 ] Alcohol Phenol

Ether

12 ] Aldehyde Ketone

Carboxylic Acid

13 ] Compounds

containing Nitrogen

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12th Chemistry

Nomenclature : Common – IUPAC

Methods of preparation / Name Reactions

Chemical Properties / Action of different reagents

Physical Properties

Reaction Mechanism / Effect of Substituent

Resonating Structures

Intext & Exercise Question - MCQ’S

Exceptional Questions

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What is hydride shift ? Consider the following reaction : 3 – methylbutan –

2 – ol heated with Hi to form 2 – iodo – 2 – methylbutane ( and not 2 – iodo –

3 – methylbutane ). This can be explained on the basis of hydride shift.

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What is hydride shift ?

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Secondary carbocation rearranges to a more stable tertiary carbocation by a

hydride ion shift. Nucleophile P ion attacks tertiary carbocation to give

tertiary alkyl iodide.

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Phenol is therefore ortho and para directing.

These resonance structures (canonical forms) have negative charge at

ortho and para positions as shown above. Hence phenol gives

electrophilic substitution reactions at ortho or para or at both the

positions but never at meta positions. Phenol is therefore ortho and

para directing.

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The ortho and para nitrophenol can be separated by steam distillation.

O – 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.

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12th Chemistry

14 ] Biomolecules

15 ] Polymers

16 ] Chemistry in

Every Day Life

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12th Chemistry

Classification of carbohydrates, Theory, Definitions, Structures

Different classes of drugs, Uses, Side effects

Polymers, Classification, Methods of preparation, Uses

Reaction of glucose, Pyranose, Fructanose Structures.

Intext & Exercise Question - MCQ’S


Structure of Cellobiose

The celloboise contains

1 → → 4 β β glycoside bond.

The structure of proteins show that large number of α - amino acid molecules are

linked to one another through peptide ( – CO – NH – ) linkage.

The peptide linkage is formed by elimination of water molecule from the amino

( – NH2 ) group of one α – ammo acid molecule and the – carboxylic ( – COOH )

group of the next neighbouring α - amino acid molecule.

These carboxylic ( – COOH ) and amino ( – NH2 ) groups undergo condensation

with other α – amino acids. Many peptide linkages thus formed are called polypeptide.

If the molecular weight of such peptides is up to 10,000 then, it is known as

polypeptide and those having molecular weight above 10,000 are known as protein.

Peptide linkage formation

Increased blood clotting timeGreen leafy vegetablesVitamin K9.

Increased fragility of RBCs and muscular weakness

Vegetable oils like wheat germ oil, sunflower oil, etc.

Vitamin E8.

Rickets (bone deformities in children ) And osteomalacia

( soft bones and joint pain in adults )

Exposure to sunlight, fish and egg yolk

Vitamin D7.

Scurvy ( bleeding gums )Citrus fruits, amla and green leafy vegetables

Vitamin C( Ascorbic acid )

6.

Pernicious anaemia ( RBC deficient in haemoglobin )

Meat, fish, egg and curdVitamin B125.

ConvulsionsYeast, milk, egg yolk, cereals and grams

Vitamin B6

( Pyridoxine )

4.

Cheilosis ( fissuring at corners of mouth and lips ), digestive disorders and burning sensation of

the skin.

Milk, eggwhite, liver, kidney

Vitamin B2

( Riboflavin )

3.

Beri beri ( loss of appetite, retarded growth )Yeast, milk, green vegetables and cereals

Vitamin B1

( Thiamine )

2.

Xerophthalmia ( hardening of cornea of eye ) Night blindness

Fish liver oil, carrots, butter and milk

Vitamin A1.

Deficiency diseasesSourcesName of VitaminesNo.

Some important Vitamins, their Sources and their Deficiency Diseases

Vitamins

Preparation of some important addition polymers

Polyacrylonitrile ( PAN or Orlon ) : -

The addition polymerization of acrylonitrile in

presence of a peroxide catalyst leads to the formation

of polyacrylonitrile.

Polyacrylonitrile is used as a substitute for wool in

making commercial fibres as orlon or acrilan.

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Antiseptics : The chemical substances which either kill or prevent the growth of

micro-organisms are called antiseptics. They are safe to be applied on to the living

tissues. e.g. Dettol, iodine, iodoform, boric acid etc.

General uses of antiseptics :

These are not harmful to living tissues and can be safely

applied to wounds, cuts, ulcers and diseased skin surfaces

These are used to reduce odors, resulting from bacterial

decomposition of the body or in mouth.

Therefore they are mixed with face powders, deodorants

and breath purifiers.

These are used in antiseptic cream like soframycin and

furacin.

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Examples of Antiseptics

Bithional : It is a bacteriostatic agent (inhibits the

growth of micro organisms), used as an agricultural

fungicide. It is used as an anti-infective in deodorants,

shampoos & surgical soaps. lt can cause skin allergy

when exposed sunlight hence not used in cosmetics.

Dettol : It is solution of chloro - xylenol is

used in antiseptic cream and for disinfecting

surgical instruments.

Phenol : They are used for dressing of small wounds. It causes severe burns,

hence other phenolic compounds are used.

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Examples of Antiseptics Iodine ( I2) : Tincture of iodine is used as a topical antiseptic to kill bacteria. It is

also used in cleaning wounds and sterilizing skin before surgery. It is also used for

disinfection of water, air and sanitization of food utensils.

Iodoform ( CHI3 ): It is used as an external antiseptic for wounds.

Boric acid ( H3BO3 ) : It is a mild antiseptic, used by swimmers as ear drops to

destroy fungal growth. It is also used for eyewash and also as a food preservative

Hydrogen peroxide : It is used as a mild antiseptic, for cleaning ears, sterilizing

surgical or medical instruments. It is also used in treating skin spots, killing the

fungus, dental hygiene and for avoiding contagious diseases. It is used as

germicidal due to release or nascent oxygen.

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Cleansing agents : Soaps and detergents.

Mechanism of cleansing action of soaps and detergents : -

Soap and detergents have two parts, a long chain of hydrocarbon tail soluble in oil

and other part (head) soluble in water.

When soap is added to an oily part of cloth or vessel, the hydrocarbon part of soap

dissolves in oil and ionic end of soap dissolves in water.

The soap molecules form micelles where one of the molecules is towards the oil

droplet while ionic end faces out side.

This results in an emulsion in water. The soap micelle assist in dissolving the dirt in

water, thus we can wash our clothes.

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Tranquilizers

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hsc chemistry preparation tips part - ii

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