Which of the following molecules,in pure form | vedclass

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(A) The stability of cyclic conjugated systems can be predicted by $H$ückel's rule.$(A)$ $1,3$-cyclohexadiene is a stable non-aromatic molecule.$(B)$

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$ (B, C) $

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(A) The stability of cyclic conjugated systems can be predicted by $H$ückel's rule.$(A)$ $1,3$-cyclohexadiene is a stable non-aromatic molecule.$(B)$ Cyclobutadiene is a $4n$ $\pi$-electron system $(n=1)$,making it antiaromatic. It is highly reactive and unstable at room temperature.$(C)$ Cyclopentadienone is antiaromatic because it has $4$ $\pi$-electrons in the ring (the carbonyl oxygen withdraws electron density,but the ring itself is antiaromatic). It dimerizes rapidly at room temperature.$(D)$ Cycloheptatrienone (Tropone) is stable due to the contribution of the aromatic tropylium cation resonance structure.Therefore,molecules $(B)$ and $(C)$ are unstable at room temperature.

Which of the following molecules,in pure form,is (are) unstable at room temperature?
$(A)$ $1,3-$cyclohexadiene
$(B)$ Cyclobutadiene
$(C)$ Cyclopentadienone
$(D)$ Cycloheptatrienone (Tropone)

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Which of the following molecules,in pure form,is (are) unstable at room temperature?$(A)$ $1,3-$cyclohexadiene$(B)$ Cyclobutadiene$(C)$ Cyclopentadienone$(D)$ Cycloheptatrienone (Tropone)