Hollymae764
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Why do London forces occur between polar molecules? I know that London Forces occur between all molecules but I don't understand how.
With non polar molecules, the shift in electrons causes it to become instantaneous and induce other non polar molecules and they attract and that's the London force. But how does this happen between polar molecules because a shift in their electrons would still mean their polar and they will already be attracted to their other polar molecules so nothing is induced or becomes instantaneous.

Someone please explain this to me
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Pigster
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(Original post by Hollymae764)
Why do London forces occur between polar molecules? I know that London Forces occur between all molecules but I don't understand how.
With non polar molecules, the shift in electrons causes it to become instantaneous and induce other non polar molecules and they attract and that's the London force. But how does this happen between polar molecules because a shift in their electrons would still mean their polar and they will already be attracted to their other polar molecules so nothing is induced or becomes instantaneous.

Someone please explain this to me
We consider decane as non-polar as all the dipoles (between C and H) cancel out, as there is symmetry. Molecules will attract each other by London Forces.

Now consider 1-chlorodecane, most of the molecule is non-polar and therefore will attract by London Forces. The polar ends of the molecules can attract each other by dipole dipole attractions. But which IMF is stronger? Most probably the LDF are more important (read stronger) than the DD.
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dj_ad_1
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(Original post by Hollymae764)
Why do London forces occur between polar molecules? I know that London Forces occur between all molecules but I don't understand how.
With non polar molecules, the shift in electrons causes it to become instantaneous and induce other non polar molecules and they attract and that's the London force. But how does this happen between polar molecules because a shift in their electrons would still mean their polar and they will already be attracted to their other polar molecules so nothing is induced or becomes instantaneous.

Someone please explain this to me
london forces occur due to the 'Molecules that undergo this instantaneous increase in their dipole are then able to induce an increase in the dipoles of other molecules.' I assume polar molecules are more likely to have an instantaneous increase in their dipoles.
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