Chemistry question dipole

Hi, please could I have help on this question? I thought the answer would be C or D by looking at the electro negativity difference but the answer is B? I’m not really sure how to workout which one has the largest dipole?

Here is the question; https://app.gemoo.com/share/image-annotation/584501545956655104?codeId=M0GGe4Wa6xRxN&origin=imageurlgenerator

Thanks!

its not D because its symmetrical and that means the dipole cancels out. Its couldn't be C because the oxygen is 2- but this is cancelled out by the two Cl-. B has the oxygen which has 2- and the two h+ which is a dipole because of the difference in charge within the molecule (two equal and opposite charges)

Ohhh ok so it’s d because there’s -2 on oxygen and overall +2 on hydrogen and since there’s a positive and negative pole, it’s the dipole and it wouldn’t be A or D because they are symmetrical so there is no overall dipole?
Thanks

yes that right!

Hi sorry, this is question is really similar https://app.gemoo.com/share/image-annotation/584602839434248192?codeId=v6gg4yGkYa1Ea&origin=imageurlgenerator and I kind of get how the answer would be B but how would you work out the polarity of CH3? Thanks!

I'm not sure if this answers your question but looking at ch3 by it self it is non-polar because C and H have similar electronegativities

if the ch3 is non polar and the oxygen is polar would that still result in a dipole moment because the answer is b?

its the c not the ch3 that induces the dipole