Write resonance structures of `CH_(2)=CH–CHO`. Indicate relative stability of the contributing structures.

Explanation

I. Most stable, more number of covalent
`CH _(2) = underset( I) (CH) - overset( :O":")overset(||) (C) - H harroverset(+)(C) H _(2)- underset(II) (CH) = overset(overset(* *) :O":")overset(|) (C ) - H`
`harr :CH _(2) - underset(III) (CH) = overset(":"O":"^(+))overset(|) (C) - H `
Stability: `I gt II gt III`
bonds, each carbon and oxygen atom has an octet and no separation of opposite charge II: negative charge on more electronegative atom and positive charge on more electropositive atom, III: does not contribute as oxygen has positive charge and carbon has negative charge, hence least stablé).