polarity of C=O bond

[binayakafle]

I m confused about this. Why presence of (electron releasing) alkyl group increases
polarity of C-X bond in haloalkane but decreases polarity of C=O bond in aldehydes and
ketones?

[Russ]

I'm a bit confused by the question, can you make it simpler?

I think what you're asking is why additional groups affect the polarity of bonds - as far as I know the C=O bond remains the same but the electron densities differ because there are now other elements connected to the C atom