Question

Which bond in urea is most polar?
(P.S. I tried C-O and N-C-O, but it's incorrect)

Answer 1

prntscr(dot)com/575lta

Answer 2

I would have guessed C=O also. Try them but look up the electronegativity of each; I don't remember them that well.
O is about 3.5
N about 3
C about 2.5
H about 2.1
difference is about 1 for C=O
about 0.9 for NH
about 0.5 for N-C
I have a copy of a periodic table that touts better numbers. If I use them it has
N = 3.04
H = 2.20 for a difference of 0.84
C = 2.55
O = 3.44 for a difference of 0.89
but that says go with C=O also.
Look in your text/notes and go with those numbers.