problem solving techniques - studiestoday.com class 12... · uses of vant hoff factor different no...

8

8

PROBLEM SOLVINGTECHNIQUES

Downloaded from www.studiestoday.com


9

9

ELECTROCHEMICAL SERIES

R R R

REDUCTION POTENTIAL REDUCED RIGHT

HIGHER THE REDUCTION POTENTIAL MORE EASILY REDUCED PLACED AT RIGHT

1. Formation of electrochemical cell

2. Calculation of E0 &e.m.f cell

3. Study of displacement reaction

4. Prediction of feasibility of redox reaction

5. Protection of metal from corrosion.

6. Prediction of the product of electrolysis

PRODUCT OF ELECTROLYSIS

MOLTEN ELECTROLYTE Aq.ELECTROLYTE

OPPOSITE IONS ARE NEUTRALISEDAT OPPOSITE ELECTRODE

Inert electrode Same metal electrode

in case of (- ve ions)

Simple ion is oxidised at anode

in case of (+ ve ions)

Cathode reaction issame but None of thenegative ions areOxidised at cathodein stead of allnegative ionsElectrodes itselfoxidised

Higher reduction potential is reduced at cathode



10

10

An aqueous solution of AgNO3 with silver electrodes.An aqueous solution of AgNO3 with platinum electrodes


AT CATHODE OUT OF Ag+ AND H+ ,Ag+ IS REDUCEDDUE TO HIGHER REDUCTION POTENTIAL

AT ANODE OUT OF OH- & NO3 –, OH- IS SIMPLE IONS SO OXIDISEDwith platinum electrodes

IF Ag ELECTRODES IS USE- CATHODE REACTION IS SAME

AT ANODE INSTEAD OF ALL –IVE IONS Ag ELECTRODE IT SELF OXIDISED

H & Cu,Ag Hg

H WITH OTHER

Prediction of feasibility of redox reaction


What would happen if Nickel spatula is usedto stir a solution of CuSO4?E0Cu2+ / Cu = 0.34 V, E0Ni 2+ / Ni = -0.25V?

. SOLUTION – CONTAINER = POSITIVE VALUE THAT CANNOT BE STORED

Cu2+ IS SOLUTION

Ni IS CONTAINER

0.34 – (-0.25) = 0.59 IS POSITIVE VALUE

CANNOT BE STORED/USED



11

11

USES OF VANT HOFF FACTOR

DIFFERENT NO OF MOLE SAME NO OF MOLE

COLLIGATIVE PROPERTY α i α I/molar mass3% urea&3% GLUOSE

CALCULATE i

FREZING POINT ,VAPOUR PRESURE α I/ i

OTHER COLIGATIVE PROPERTIES α i

0.1 M UREA &0.1M NaCl

P BLOCK ELEMENT



12

12

MO

If p

No

BOND ORDER

BOND ORDER OF DIATOMICLECULES / IONS BOND ORDER OF

POLATOMICMOLECULES / IONS

-electrons are up to 6

of p–electrons = BO2

If p-electrons > 6

Total no of bondB

O Total no of resonating structure

6 – more p electrons than 6 = BO2

BOND ANGLE

HYBRIDISATION IS SAMELONE PAIRS ARE DIFFERENT

HYBRIDISATIONIS SAME LONEPAIRS ARE SAME

Bond angle α 1/no of lone pairs Bond angle α electronegativity α 1/size

PH4+ & PH3

NH3 & PH3



13

13

BOND POLARITY

DIATOMIC MOLECULE POLYATOMIC MOLECULE

HomoatomicNon polar

HeteroatomicPolar

Regular moleculeOnly bond pair Irregular molecule

Lone pair

I2 ICl Polar

Same surrounding elementNon polar

Different surrounding elementpolar NH3

BOND LENGTH

BOND LENGTHS ARE SAME BOND LENGTHS ARE DIFFERENT

DUE TO RESONANCE DUE TO ELECTRONIC REPULSION



14

14

ACIDIC PROPERTIES

NON OXOACID OXOACID

ACIDIC NATURE α SIZE α 1/B.E ACIDIC NATURE α STABILISATION OFCONJUGATE BASE

HI > HBr > HClHClO4 > HClO3 > HClO2 > HClO

BASIC NATURE

HYDROXY BASE (-OH PRESENT ) NON HYDROXY BASE ( -OH NOT PRESENT)

OH- REMOVAL CAPACITY H+ ATTRACTION CAPACITY

BASIC NATURE α SIZE α 1/BE BASIC NATURE α ELECTRONEGATIVITY

KOH > NaOH > LiOH NH3 PH3 AsH3



15

15

REDUCTION PROPERTIES

HYDRIDEOXOACID

REDUCTION PROPERTIES α SIZE α 1/B.E REDUCTION PROPERTIES α NO OF (E-H)SINGLE BOND

H2S < H2Te H3PO2 > H3PO3

BOILING POINT

MOLECULAR FORCE

HYDROGEN BONDING VANDERWAAL FORCE

B. P α MOLECULAR MASS α 1/ branching



16

16

OXOACID OF PHOSPHORUS

STRUCTURE TETRAHEDRAL AT LEASTONE P=O AND ONE P-OH GROUP,

FUNCTION NUMBER OF P-OHBOND =BASICITY

NUMBER OF P-H BOND=REDUCTIONCAPACITY

TYPE OF OXOACID

ORTHO- PARENT ACIDPYRO- 2 X ORTHOACID-H2OHYPO – ORTHOACID-OMETA-ORTHO ACID-H2OPEROXOMONO-ONE-OH IS REPLACED

BY – OOHPEROXODI- FROM PYRO – O-IS

REPLACEDBY –OO-

COMPARASION OF OXIDATION STATE BOTTOM ELEMENT AND OTHER –INERT PARE EFFECT

COMPARASION OF PHYSICAL STATE OF THE SECOND PERIOD &AND THIRDPERIOD ELEMENTS---- P∏-P∏ BONDING

INCREASE OF COVALENCY –VACAND d ORBITAL

LOWEST OXIDATION STATE -OUTERMOST ELECTRONS-8, STABILITY DECREASESDOWN THE GROUP DUE TO ELECTRONEGATIVY DECREASES

HIGHEST OXIDATION STATE =OUTERMOST ELECTRONS STABILITYDECREASES DOWN THE GROUP-DUE TO INERT PAIR EFFECT

CATENATION PROPERTY α B.D.E α 1/SIZE α 1/ELECTRONIC REPLUCTION

THERMAL STABILITY α 1/SIZE

OXIDISING POWER OF OXO ACID DECREASES WITH INCREASE OF OXIDATION STATE



1717

17

Meta

IE α

llic and non metalliccharacter

1/Metallic property

IONISATIONENTHALAPY

Stability of oxidation state

METALLIC AND NONMETALLIC NATURE

BOND ENTHALPY

∆EN α 1/BONDLENGTH

BOND

ENERGY αELECTRONEG

ATIVITYDIFFRENCE

ACIDIC STRENGTH OF HYDRIDEBOND ENERGY α STABILITY

OF MOLECULE

APPLICATION OFELECTRONEGATIVITY

REACTIVITYDIFFRENCE IN

ELECTRONEGATIVITY α STABILITYα 1/REACTIVITY

NATURE OF BOND ANDPRCENTAGE OF IONIC CHARECTER

NOMENCLATURE OFINORGANIC

COMPOUNDSOF2 OXYGEN DIFLORIDE

ACIDIC NATURE OFTHE OXIDE α

ELECTRONEGATIVITY

NATURE OF HYDROXIDE



1818

18

HYBRIDISATION STATE

TOTAL σ bond pair+ lone pair=Hybridisation state

Organic chemistry



1919

19

/+I

ACID

NUCLEOPHILIC SUBSTITUTION

SN2 SN1

STERIC HINDRANCE,NATURE OF LEAVING GROUP

S T A B I L I T Y O F C A R B O C A T I O NN A T U R E O F L E A V I N G G R O U P

Stability of Carboanion

Stability of (C –) α –I

INDUCTIVEEFFECT POLAR

ITY OFORGA

NICCOMPOUND

IC STRENGTH

Acidic Strength α -I/+I



2020

20

ing St

Electron den

Stability of Carboanion

Stability α No of resonat

RESONANCEEFFECT Reactivity of

BenzeneTowards

electrophilicsubstitution

ACIDC NATURE

BASIC NATURE

Basic nature α +R, +I/-R, -I

sity increases by resonance H + attraction capacityMore basic & vice-versa

Directive nature of group attached to benzene

Ortho/para directingContain lonepair electron

Meta directingDouble bond/triple bond presentThat must attach to one moreElectnegative element

+R effect -Reffect

-OH,-OR,-NH2 -CHO,-COOH,-SO3H



problem solving techniques - studiestoday.com class 12... · uses of vant hoff factor different no...

Documents