Kerala Plus Two Chemistry Notes

PLUS

2 NOTES
Chapter Wise

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1.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

➢ Henry's law:

“As the pressure of gas increases solubility of gas in liquid also increases”
OR
Partial pressure (p) of the gas in vapour phase is proportional to the mole
fraction (X) of the gas in the solution.

ie P=K H X (KH is Henry's constant)

Applications of Henry's law:

(i) To increase the solubility of CO2 in soft drinks or soda.
(i) Bends experienced by Scuba divers.
(iii) Anoxia experienced by peoples at high altitude

➢ Effect of temperature
The solubility of a gas in a liquid decreases with increase in temperature
Therefore aquatic life is more comfortable in cold water than hot water.

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 A
PA=P0AX A
and for component B
PB=P0BXB

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Ideal solution:
The solution which obeys Raoult's law are called ideal solutions.
∆ H mix =0
∆ V mix = 0
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

Non ideal solution
The solution which does not obey's Raoult's law are called Non ideal solutions.
∆ H mixǂ0
∆ V mix ǂ 0
Non ideal solution divided into two

➢ Non ideal solution showing Positive deviation from Roults law:

A-B interaction less than A-A and B-B interaction.
∆ H mix>0
∆ V mix >0
Eg:- Ethanol and acetone

➢ Non ideal solution showing Negative deviation from Roults law:

A-B interaction greater than A-A and B-B interaction.
∆ H mix<0
∆ V mix <0
Eg: Chloroform and acetone

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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.

They are two types-
➢ minimum boiling azeotrope
The solutions which show a large positive deviation from Raoult’s law
 maximum boiling azeotrope
The solutions which show large negative deviation from Raoult’s law.
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 using the following
equations

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Osmosis , Osmotic Pressure and 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. This
process
is called reverse osmosis. Reverse osmosis is used in desalination of sea water
and in water purifiers.
Isotonic, Hypotonic & Hypertonic Solutions
The solutions having same osmotic pressure 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
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.

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

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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).

UNIT.2
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 ZnSO4 solution and a Cu rod in
CuSO4 solution. The two solutions are connected externally by a metallic wire
through a voltmeter and a switch and internally by a salt bridge.

(i)Cu 2+ + 2e - → Cu(s) (Reduction /In right half cell)
(ii) Zn(s) → Zn 2+ + 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

Electrode Potential(Ecell )
The tendency of a metal to lose or gain electron when it is in contact with
its own solution is called electrode potential,(E el ). Electrode potential measured
at standard conditions is known as Standard electrode potential(E 0cell ).

The cell potential is the difference between the electrode potentials (Reduction

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potentials) of the cathode and anode.
E cell = E cathode - E anode
E cell = E right - E left

the symbolic cell representation of Daniel cell is
Zn (s)/ Zn 2+(aq) //Cu 2+(aq) /Cu (s)

Variation of Molar conductivity ( Λm ) with dilution

For both strong and weak electrolyte, the molar conductivity increases with
dilution 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 Λ m for
strong and weak electrolytes is shown in the graphs For strong electrolytes, the
value of ʌm0 can be determined by the extrapolation of the graph.

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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

Λm 0= 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
1.Determination of ʌm0 of weak electrolytes.

2.Determination of degree of dissociation of weak electrolytes

α= ʌm
ʌm0

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.

Batteries/ Commercial cells

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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.

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) + 2H2 O (l ) + 4e – → 4OH –(aq)
Anode: 2H 2 (g) + 4OH –(aq) → 4H2O (l) + 4e –
Overall reaction is: 2H2(g) + O2(g) → 2H 2 O (l )

Advantages

1.The cell works continuously as long as the reactants are supplied.
2. It has higher efficiency
3. It is eco-friendly (i.e. pollution free)
4. Water obtained from H 2 – O 2 fuel cell can be used for drinking.

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 (Fe 2 O 3 . x H 2O)

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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.

UNIT.3
CHEMICAL KINETICS

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

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) + I 2 (g)

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,
instantaneous rate is given by

Factors affecting rate of a reaction
1. Concentration of the reactants
2. Temperature
3. Presence of catalyst

Dependence of rate of reaction on concentration:
For a general reaction, aA + bB → cC + dD,

Rate α [A] X [B] Y

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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
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
Unit of Rate constant mol1-n Ln-1 sec-1
Where n is Order of reaction

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.
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.
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.)

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
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

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 Inversion of cane sugar
 Ester hydrolysis
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

Integrated rate equation of first order reaction

Integrated rate equations

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Half life of a reaction ( t 1/2 )

It is the time required for half of the reactant converted in to product

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

Temperature Dependence of the Rate of a Reaction Reaction
Arrhenius equation

This is an equation which relates rate constant with temperature

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

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Activation energy (Ea):
The energy requierd to form an activated complex
Activation energy (E) = Threshold energy - Actual energy possessed by reacting
molecules
Effect of Catalyst
Catalyst provides an alternate path of lower activation energy to the reactant
molecules.

Threshold energy:
The minimum energy that the reacting molecules must posses in order to
undergo effective collisions to form product is called threshold energy.

UNIT 4.
d and f BLOCK ELEMENTS

General properties of transition elements
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.,

For example ,
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] 4s 2 3d 5 the divalent ion
in aqueous solution will have configuration
[Ar]4s 0 3d 5
d 5 configuration (five unpaired electrons).
The magnetic moment, μ is

Formation of Coloured Ions
Colour of transition metal is due to d-d transitionIon with d 0 and d 10 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
Complex Formation
A few examples K 4 [Fe(CN) 6 ] , K 3 [Fe(CN) 6 ]
Transition metals forms number of complex compounds. This is due to

a)smaller sizes of the metal ions,
b)their high ionic charges

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c)availability of d orbitals for bond formation.
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
Oxidation state
Transition elements show variable oxidation states because energies of ns sub
level and (n-1)d sub level are almost equal.
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.
Alloy formation
Transition elements form alloys due to similar size e.g. Manganese steel
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
POTASSIUM DICHROMATE
Preparation

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Properties of Potassium dichromate

POTASSIUM PERMANGANATE
Preparation

Generally prepared From Pyrolusite ore ( MnO 2 )

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Lanthanoids
Lanthanoids are 14 elements coming after Lanthanum starting from
Lutetium and ends in Lawrencium .
The common oxidation state of lanthanoid is +3. Example La 3+ ,Ce 3+ .......
Lanthanoid contraction
Steady and slow decreasing of atomic and ionic radii of lanthanoids from
La to Lu3+ is called as Lanthanoid contraction.
3+

Reason for lanthanoid contraction
ineffective shielding effect of 4f orbital
Consequence of lanthanoid contraction
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
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.

UNIT 5
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– , H 2 O , NH 3 etc..,
Didentate :- When a ligand can bind through two donor atoms as in the ligand is
said to be didentate
Example H2 NCH 2 CH 2 NH 2 (ethane-1,2-diamine) or C 2O4 2– (oxalate),
Polydentate:-when several donor atoms are present in a single ligand the ligand
is said to be polydentate.
Example N(CH2 CH 2 NH2 )3,

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Note:- Ethylenediaminetetraacetate ion (EDTA 4–) is an important hexadentate
ligand. It can bind through two nitrogen and four oxygen atoms to a central
metal ion

Homoleptic complexes:
Those complexes in which metal or ion is coordinate bonded to only one kind
of donor atoms. For example: [Co(NH3 ) 6 ] 3+
Heteroleptic complexes:
Those complexes in which metal or ion is coordinate bonded to more than one
kind of donor atoms. For example: [CoCl2 (NH3 ) 4 ] + , [Co(NH3 )5 Br] 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.
Ionisation isomerism
These type of isomerism arises because of the capability of

coordination compounds to produce different ions in solution.

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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 6H 2 O

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.

Coordination isomerism
This type of isomerism arises from the interchange of ligands between cationic
and anionic entities in the complex..

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..)

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Octahedral complexes

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 [PtCl 2 (en) 2 ] 2+ , only the cis-isomer
shows optical activity

Valence bond theory:
a) According to this theory, the metal atom or ion under the influence of ligands
can use its (n-1)d, ns, np or ns, np, nd orbitals for hybridisation to yield a set of
equivalent orbitals of definite geometry such as octahedral, tetrahedral, and
square planar.
b) These hybridised orbitals are allowed to overlap with ligand orbitals that can
donate electron pairs for bonding.
Crystal Field Theory:
a) It assumes the ligands to be point charges and there is electrostatic force of
attraction between ligands and metal atom or ion.
b) It is theoretical assumption.

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UNIT 6
HALO ALKANES AND HALO ARENES

Halo alkanes or Alkyl halides are having general formulae R-X Example
CH3 Cl , C2H5Cl 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

Addition of hydrogen halides: By reaction with HCl.HBr,HI Propene yields two
products, however only one predominates as per Markovnikov’s rule.

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(ii) From Alcohols ( R-OH )
Here the hydroxyl group of an alcohol is replaced by halogen

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.

(a) Substitution nucleophilic bimolecular (SN 2)
SN2 reaction occurs in one step.
This mechanism proceeds through inversion of configuration , in the same way as
anumbrella is turned inside out when caught in a strong wind.
The reaction between methyl chloride CH3Cl and hydroxide ion OH- to yield
methanol CH3OH and chloride ion Cl- is example

Rate
depends upon the concentration of both the reactants. So it follows second order
kinetics.

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The order of reactivity of alkyl halides towards SN2 reaction
Primary halide > Secondary halide > Tertiary halide
Substitution nucleophilic unimolecular (SN1 )
➢ S N 1 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

The order of reactivity of alkyl halides towards S N 1 reaction
Tertiary halide > Secondary halide > Primary halide

HALO ARENES
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 we get a halo benzene. This reaction is called
Sandmeyer’s
reaction .

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Important Electrophilic substitution reactions of Halo arenes are
(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

Sulphonation :-
On sulphonation using Conc. H2SO4 , chloro benzene gives ortho chloro
benzene sulphonic acid and para chloro benene sulphonic acid ( major product).

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(iv) Friedel-Crafts alkylation
Chloro benzene when treated with methyl chloride (CH3 -Cl) in presence of
anhydrous AlCl 3 , we get p-chloro toluene as the major product and o-chloro
toluene as minor product

Friedel-Crafts acylation :
Chloro benzene when treated with acetyl chloride in presence of anhydrous
AlCl3 we get p-chloro acetophenone as the major product an o-chloro
acetophenone as minor product

UNIT 7.
Alcohols, Phenols and ethers

1.Preperation of alcohols

a) From carbonyl compounds
Aldehydes on reduction give primary alcohol and ketones give secondary alcohol

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b) From Grignard reagent RMgX

2.Preparation of Phenols

Chlorobenzene is fused with NaOH

b) From diazonium salts
Aniline is treated with nitrous acid (NaNO2 +HCl) at 273-278k to form
benzene diazonium chloride. It is then warmed with water to form phenols.

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Chemical properties of Alcohols
a) Luca’s test (Reaction with Hydrogen halides)
Alcohols react with Hydrogen halides to form alkyl halides.

1°alcohol, 2°alcohol, 3°alcohol can be distinguished by using Luca’s reagent
(ConcHCl+ZnCl2 )
3°alcohol produce turbidity immediately. 2°alcohol produce turbidity within 5
minutes.
1°alcohol do not produce turbidity at room temperature.
b) Dehydration
Alcohols undergo dehydration to form alkenes

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Chemical properties of Phenols
a) Nitration of phenol (Electrophilic substitution)

Some important commercial alcohols-Ethanol
Ethanol is obtained by the fermentation of sugar.

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Ethers

Preparation of Ethers-
Williamsons Synthesis
An alkyl Halide is treated sodium alkoxide.

Properties of Ethers

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UNIT 8
Aldehydes, ketones and carboxylic acids

I)Preparation of aldehydes and ketones
1) By the oxidation of alcoholsAldehydes and ketones are prepared by
oxidation of primary alcohols and secondary alcohols.

2)By dehydrogenation of alcohols
Dehydrogenation of 1° alcohol gives aldehyde.

3)Rosenmunds reduction
Acid chloride is reduced in presence of palladium and Barium sulphate.

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5) Gattermann-Koch Reaction
When benzene is treated with CO, HCl in presence of anhydrous aluminum
chloride, it gives benzaldehyde.

6.Friedel Crafts reaction
When benzene is treated with acid chloride in presence of anhydrous aluminium
chloride, corresponding ketone is formed.

Chemical reactions of Aldehydes and ketones
1.Reduction

a) Reduction to alcohols

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Aldehydes on reduction with Lithium aluminium hydride or H2 in presence
of Ni, Pd gives 1° alcohols.

b) Reduction to hydrocarbons. Here -CO- group is reduced to -CH 2 with Zinc
amalgam and conc. HCl (Clemmensen reduction)

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II) Carboxylic acids
Methods of preparation of carboxylic acids
1.From primary alcohols and aldehydes
Primary alcohols are readily oxidized to carboxylic acid.

2.From alkyl benzene
Aromatic carboxylic acid can be prepared by the oxidation of alkyl benzene with
acidic or alkaline KMnO4

34 PLUS TWO HSE /VHSE CHEMISTRY 2022-23 BY KANNUR DISTRICT PANCHAYATH

2.Reduction
Carboxylic acids are reduced to primary alcohols with Lithium aluminium
Hydride or Diborane.

3.Hell-Volhard-Zelinsky reaction
Carboxylic acids undergo α-halogenation with Cl2 , Br2 in presence of red
phosphorus gives α-halo carboxylic acids.

4.Ring Substitution
The -COOH group is a deactivating group and meta-directing. So, on
electrophilic substitution reactions, they give meta derivative product.

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UNIT 9
Amines

I)Preparation of Amines
1.Reduction of Nitriles

Hoffmann Bromamide degradation reaction
A primary amine is treated with Bromine and aqueous NaOH. The amine so
formed contains one carbon atom less than the parent amide.

Chemical reactions of Amines
1. Carbylamine reaction
Aliphatic and aromatic primary amine is heated with chloroform and alcoholic
KOH to form isocyanides (Carbylamines) with foul smell.

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Tertiary amines do not react with Hinsberg reagent.

III) Chemical reactions of Diazonium salts
a.Sandmeyer’s Reaction
Benzene diazonium chloride is treated with cuprous halide and halogen acids to
form Halo benzenes.

UNIT 10
BIO MOLECULES

The molecules present in living system like carbohydrates, proteins,
nucleic acids, lipids, vitamins etc. which are essential for the growth and
maintenance of our body are called Biomolecules.
1.Carbohydrates ( Saccharides )
They can be defined as polyhydroxy aldehydes or ketones or the
compounds which produce such units on hydrolysis.
Sugars:- Carbohydrates which are crystalline, water soluble and
sweet in taste are called as sugars. Eg: Glucose, Fructose
Non-sugars :- Carbohydrates which are not crystalline, water
insoluble and have no sweet taste are called non-sugars. Eg: Cellulose
2.Classification of carbohydrates
Based on their behaviour on hydrolysis:
Based on this, carbohydrates are classified into three types:
 Monosaccharides: These are carbohydrates which cannot be hydrolysed in to

simpler units of polyhydroxy aldehydes or ketones. E.g. glucose, fructose, ribose,
galactose etc.

 Oligosaccharides: These are carbohydrates which give two to ten
monosaccharide units on hydrolysis. They are further classified as disaccharides,
trisaccharides, tetrasaccharides etc. E.g.Sucrose, maltose, lactose.
 Polysaccharides: These are carbohydrates which give a large number of
monosaccharide units on hydrolysis. E. . starch, cellulose, glycogen etc.

Carbohydrates Monomers
Sucrose Glucose, Fructose
Maltose Two units of Glucose
Lactose Glucose,Galactose
Starch,Cellulose, Glycogen A large number of Glucose units

Based on their reducing character:
Based on this, carbohydrates are of two types - reducing sugar and non-reducing sugar.
 reducing sugars :- Carbohydrates which contain free aldehydic or ketonic
groups. All monosaccharides are reducing sugars. Disaccharides like maltose
and lactose are also reducing
 non-reducing sugars.: Those which do not contain free aldehydic or ketonic
group.sucrose is non-reducing
 Preparation of glucose
From sucrose (Cane sugar): If sucrose is boiled with dilute HCl or H 2SO2 in
alcoholic solution. glucose and fructose are obtained in equal amounts.
C12 H22 O11 + H2 O C6 H12 O6 + C6 H12 O6
4.Glycosidic Linkage
During the formation of a disaccharide or polysaccharide, the
monosaccharide units are joined together through C-0-C linkage. Such a linkage
is called glycosidic linkage.
5. Invert Sugar
Cane sugar (sucrose) on hydrolysis gives an equimolar mixture of (+)
glucose and (-) fructose.
C12 H22 O11+ H2O C6 H12 O6 + C6 H12 O6
(+)Sucrose dextro ( +) Glucose (+52.50) laevo (-)Fructose (-92.40)

Sucrose is dextro rotatory (+) but the net optical rotation of the product
formed after hydrolysis is laevo (-). So the process is called inversion of cane
sugar and the product formed is called invert sugar.
6.Starch:
Starch is the main storage polysaccharide of plants. It is a polymer of
glucose and consists of two components— Amylose and Amylopectin.
Amylose is water soluble component which constitutes about 15-20% of
starch. It is a linear polymer of glucose units.
Amylopectin is insoluble in water and constitutes about 80- 85% of starai.
It is a branched chain polymer of glucose units.
7.Glycogen:
The carbohydrates are stored in animal body as glycogen. It is also known
as animal starch because its structure is similar to amylopectin, a branched
chain polymer of glucose units.
8.Denaturation of Protein:

When a protein is subjected to physical change (like change in
temperature) or chemical change (like change in pH), it loses the biological

activities. This process is called denaturation of protein. E.g. coagulation egg
white on boiling, curding of milk etc.
9.Nucleic acids:
They are long chain polymers of nucleotides and are responsible for
transmission of heredity. These are of two types - deoxy ribonucleic acid (DNA)
and ribonucleic acid (RNA).
The nucleotide units combine to form nucleic acid through Phospho diester
linkage.

A simplified version of nucleic acid chain is as shown below,

VITAMINS

Vitamins are organic compounds required in the diet in small amounts to
perform specific biological functions for maintenance of normal growth and
health. Vitamin –D synthesized in the body