IIT JEE , AIEEE Forum - Chemistry , Organic Chemistry

nandithac

which has a greater dipole moment CH2Cl2 or CHCl3 n why?????????

anchitsaini

CHCl3 cos there there is more polarity in C-Cl than in C-H bond

morningdew

CHCl3
That is because, this molecule will have a tetrahedral structure (see it in you mind)
Then, Chlorine, being more electronegative than Carbon, will pull electron toward itself.
Now tell me, which would cause more pulling, 2 cl atoms or 3 cl atoms?

...

That's the answer.

lokeshsardana

but according to me CH2Cl2 should hav greater dipole moment..

dipole moment is a vector quantity ......

so, in CHCl3 due to tetrahedral arrangement 3 C-Cl dipoles will result in less dipole moment as compared to CH2Cl2.......

infact , CH3Cl is having max. dipole moment among chloromethanes.........

sti

in the ist dia chci3 is shown. cl cl cancel each other. but on the otherside h-cl dipole moment exists

in 2nd dia there is no dipole moment...............since h-h and cl-cl cancel each other

there is 1 more structure possible

in 3rd dia dipole moment exists

ch2cl2 will hav greater dipole moment

morningdew

Why so?

supreet159

its chcl3 bcas the chlorine atom is more electro negative than hydrogen

lokeshsardana

xplained in previous post............

and same question has been asked in jee few years back........

nandithac

can u pls explain how 3 cl atoms will cause less dipole moment and as above sti is wrong in telling that the molecule shows geometric isomerism

lokeshsardana

u can imagine the situation like this........

u know that CCl4 is having zero dipole moment..........

suppose if we remove a C-Cl dipole from the structure

then remaining 3 C-Cl dipoles will behave as single C-Cl dipole

whose polarity is opposite to that of single C-Cl dipole which we have removed........

hence d.m of CCl3 < CHCl2

note: in the whole xplaination I have neglected the d.m of C-H bonds
4 clear understanding and if it is taken into account it will not cause any change in result ............

nandithac

THANKS YA I GOT IT NOW

narulaajun

CH2Cl2 is more polar coz its a vector qty...three Cl cancel the effect of each other

Aatish

Its CH2Cl2 coz the bond dipole of third C-Cl bond in CHCl3 reduces the net bond dipole due to the other two C-Cl bonds...........

sinjan.j

here is the perfect solution

CHCl3 have more dipole moment. in CHCl3 have two equivalent bond C-Cl which

cancel each other but one C-H bond is not cancelled with C-Cl . so dipole moment

is there. but in CHCl2 there is two equivalent bond C-Cl as well as two equivalent

bond C-H . so cancel each other so almost zero dipole moment

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