Why is CH2Cl2 polar

(Polar molecules, Non-polar molecules, etc.)

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Melody Haratian 2J
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Why is CH2Cl2 polar

Postby Melody Haratian 2J » Fri Dec 11, 2020 7:38 pm

Why is CH2Cl2 polar?
Can’t the C-Cl dipole bonds be opposite of each other and cancel each other out after having drawn the Lewis structure?

apurva-3E
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Re: Why is CH2Cl2 polar

Postby apurva-3E » Fri Dec 11, 2020 7:41 pm

Image

As seen on the drawing above, the geometry of the molecule shows that the polar bonds do not cancel each other out. Always draw the shape out because simple lewis structures won't be able to tell you if something is polar or not.

Ivan Chen 2H
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Re: Why is CH2Cl2 polar

Postby Ivan Chen 2H » Fri Dec 11, 2020 7:43 pm

As a lewis structure it would be possible. But as a 3d structure it would be impossible to place chlorine atoms opposite to each other in a tetrahedral shape, which makes it polar.

Nathan Chu 3H
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Re: Why is CH2Cl2 polar

Postby Nathan Chu 3H » Fri Dec 11, 2020 7:44 pm

If you look at the VSEPR shape of CH2Cl2, it shows that the polar C-Cl bonds have dipoles that point in different directions that do not cancel out. Therefore, the entire molecule will be polar.

Although the lewis structure might imply that the C-Cl dipoles would "cancel out", the molecule is actually not planar and the Cl-C bonds do not point in opposite directions to cancel out.

Evonne Hsu 1J
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Re: Why is CH2Cl2 polar

Postby Evonne Hsu 1J » Fri Dec 11, 2020 8:47 pm

The dipoles for this particular Lewis Structure of the compound do not cancel out, therefore this compound would be considered polar. A reminder is that you should always draw out the lewis structure before determining its polarity unless you are extremely familiar with the structure of the compound.

Rachel Kho Disc 2G
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Re: Why is CH2Cl2 polar

Postby Rachel Kho Disc 2G » Fri Dec 11, 2020 10:37 pm

Wait so does this also mean that tetrahedral molecules are usually polar? Are there any examples of nonpolar tetrahedral molecules?

Lucy_Balish_3G
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Re: Why is CH2Cl2 polar

Postby Lucy_Balish_3G » Fri Dec 11, 2020 10:40 pm

Rachel Kho Disc 1I wrote:Wait so does this also mean that tetrahedral molecules are usually polar? Are there any examples of nonpolar tetrahedral molecules?


CCl4 is an example of a molecule that is tetrahedral and nonpolar.
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