(Polar molecules, Non-polar molecules, etc.)
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The bonds between C-Cl are polar while the C-H bonds are nonpolar because the difference in electronegativities is 0.3 for C-H and 0.61 for C-Cl. Based on the idea that the En difference greater than or equal to 0.5 is polar, the C-Cl bonds will affect the molecular shape. Hope this explanation gives some insight into the image I linked with the post.
When drawing the lewis structure it might look like the dipole moments could cancel each other out if you drew it with the Cl on opposite sides, but the shape of the molecule is tetrahedral meaning the bond angles are not 90 degrees but are about 109.5, so CH2Cl2 is polar because the C-Cl bond has ionic character/a dipole moment, and the two do not cancel out leaving it polar. Looking at the shape helps to visualize.
A molecule like CH2Cl2 has dipole moments occurring at the bonds formed by C and Cl due to the difference in electronegativity. You have consider that because the molecule has four regions of electron density, its shape will be tetrahedral. In a tetrahedral molecule, the bond angles are 109.5, meaning that the dipole vectors formed by C and Cl cannot be canceled due to opposing directions. Hope this helps
CH2Cl2 would be a nonpolar molecule if the 2 C-H bonds and 2 C-Cl bonds were directly across from each other. But since CH2Cl2 is a tetrahedral molecule (4 e- regions), none of the bonds are directly across from each other so none of them cancel, resulting in a polar molecule. Hope this helps!
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