11

IsomerismIsomerismand D.Uand D.U

22IsomersIsomers Isomers:Isomers: different compounds with the same

molecular formula. Same number of carbon and other atoms. Same degree of unsaturation. Same % of elemental composition. Must have different physical or chemical

properties.

33IsomersIsomers Degree of unsaturation from Structural formula Degree of unsaturation from Structural formula It is defined as the sum of no of It is defined as the sum of no of bonds and bonds and

number of cycles in a compound.number of cycles in a compound. Example Example CyclopropaneCyclopropane bond=0 bond=0 cycle=1cycle=1 Du =1Du =1 PropenePropene bond=1 bond=1 cycle=0cycle=0 Du =1Du =1 CyclopropeneCyclopropene bond=1 bond=1 cycle=1cycle=1 Du =2Du =2 BenzeneBenzene bond=3 bond=3 cycle=1cycle=1 Du =4Du =4 NapthaleneNapthalene bond=5 bond=5 cycle=2cycle=2 Du =7Du =7

44IsomersIsomers Degree of unsaturation from Molecular formula :-Degree of unsaturation from Molecular formula :- If molecular formula of any compound is If molecular formula of any compound is

C CnnHHmmClClxxOOyyNNzz.. Where n is number of carbon atoms.Where n is number of carbon atoms. Where m is number of hydrogenn atoms.Where m is number of hydrogenn atoms. Where x is number of monovalent atoms like Where x is number of monovalent atoms like

Cl,Br,I,F etc.Cl,Br,I,F etc. Where y is number of oxygen atoms.Where y is number of oxygen atoms. Where z is number of nitrogen atoms.Where z is number of nitrogen atoms.

Then D.U=(2n+2+Z-m-x)/2.Then D.U=(2n+2+Z-m-x)/2.

55IsomersIsomers

D.U=(2n+2+Z-m-x)/2.D.U=(2n+2+Z-m-x)/2. Example Example CC44HH1010 n=4n=4 m=10m=10 DU=0DU=0

CC66HH1010 n=6n=6 m=10m=10 DU=2DU=2

CC66HH66 n=6n=6 m=6m=6 DU=4DU=4

CC44HH88CCl2l2 n=4n=4 m=8m=8 X=2X=2 DU=0DU=0

CC44HH1010O O n=4n=4 m=10m=10 y=1y=1 DU=0DU=0 C100H200Cl10O10N10 C100H200Cl10O10N10

n=100 m=200 x=10 Z=10n=100 m=200 x=10 Z=10

DU=(100x2+2+1o-200-10)/2 DU=(100x2+2+1o-200-10)/2

DU=1.DU=1.

66IsomersIsomers

77IsomersIsomers Which functional group is expected to Which functional group is expected to

be possible for Cbe possible for C1010HH2020 Cl BrO Cl BrO22 A.A. Carboxylic AcidCarboxylic Acid B. B. Acid chlorice Acid chlorice C Ketone.C Ketone. D.AlcoholD.Alcohol Ans. D (Here DU for given formula is 0Ans. D (Here DU for given formula is 0 All other functional groups requires 1 All other functional groups requires 1

Du.Du.

88Concept Developed by Concept Developed by

Chandana.