Question

In which of the following resonance will be possible?

• A. $C{H}_3-C{H}_2-C{H}_2-CHO$
• B. $C{H}_2=CH-CH=O$
• C. $C{H}_{3}COC{H}_3$
• D. $C{H}_2=CH-C{H}_2-CH=C{H}_2$

Answer 1

The correct option is B $C{H}_2=CH-CH=O$

Resonance is the delocalisation of electrons in a conjugated system.
Conjugated system is a system having alternative sigma and pi Bonds, example: Benzene.
In option (a), (c) and (d), there is no resonance as there are no alternate single and double bonds. So, the correct answer will be option (b) as there is presence of alternate single and double bond.