Which of the following molecules, in pure form, is unstable at room te

1.	Which of the following molecules, in pure form, is unstable at room temperature ?
Answer» Solution : Both (b) and (c ) are PLANAR molecules and contain cyclic CLOUDS of `4pi`-electrons and HENCE are antiaromatic. Therefore these are unstable at room temperature. Compound under option (a) ALSO contions `4pi`-electrons but these are not delocalized over the entire ring. Therefore, it is non-aromatic. Compound under option (d) contains completely delocatlized `6pi`-electrons and is also planar. Therefore, it is aromatic.

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