In $CH X_{2} = CH - CHO$ , which atom carries the greater partial positive charge among the two alkene carbons, and why?

ABoth carry equal charge, since the $C = C$ bond is non-polar
BThe terminal $CH X_{2}$ carbon, because of the +M effect of the $CHO$ group
CThe carbon attached to $CHO$ , because of the -I effect of $CHO$ alone
DThe terminal $CH X_{2}$ carbon (the carbon farther from $CHO$ ), because of the -M effect of the $CHO$ group

Answer: D

The

CHO

group withdraws pi electrons through conjugation (-M):

CH X_{2} = CH - CH = O X_{+} X_{2}^{2 +} CH X_{2} - CH = CH - O X^{-}

. This puts the positive charge on the terminal carbon. The inductive effect decays with distance, so it is not the main factor.