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dev_22oct

green is Cl and white is H

the direction of dipole moment in case of C-H bond is from H to C and they w'll combine to gv a resultant(R2) in direction of C-Cl bond and they w'll be added...

net dipole R1+R2

R1 due to C-Cl bond and R2 due to 3 C-H bond.

dev_22oct

dev_22oct

in CH₂Cl₂ R₂ w'll be less than the R₂ of CH₃Cl ...becoz in this out of 3 hydrogen 1 is replaced by Cl which has a opposite dipole moment .

lokeshsardana

dev sir and iberis22 mam,

thank u very very much for clearing my doubt............

now, I got it..........

the main mistaking which I was doing is that I calculated the dipole moments of all molecules assuming them to be perfectly tetrahedral but in reality they are not perfectly tetrahedral.........

due to greater repulsion, two Cl atoms r at greater distance as compared to two H atoms .....hence increasing Cl-C-Cl angle as compared to H-C-H angle........

thus it is not possible to calculate and guess their dipole moments.....

so, finally order of dipole moments are

CH3Cl(1.84D) > CH2CL2(1.6D) > CHCl3(1.04D) > CCl4(0D)

And pls forgive me.........I don't know what is conventional direction of dipole moment in chemistry......
but from physics point of view it should be from -ve end to +ve end...
so, it should be from C to H and from Cl to C.........

:)

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