Resonance structures of propenal are given below. Which of these resonating structures is more stable ? Give reason for your answer.
`CH_(2)=underset("I")(CH-CH)=O harr underset("II")(overset(o+)(CH)_(2)-CH=CH-overset(Theta)(O))`

Options

A. I
B. II
C. Both are equally stable
D. None of the above

Answer

A

Explanation

The structure having more covalent bonds in a resonating structure, has more stability, Further, there is charge separation in structure (II) and the terminal carbon has only a sextet of electrons in (II). These two factors makes structures (II) less stable.

Hence, `I gt II` in terms of stability