7-bromo-1,3,5-cycloheptatriene exists as ionic species in aqueous solution while 5-bromo-1,3-cyclopentadiene doesn't ionise even in presence of `Ag^(+)(aq)`, Explain.

Explanation

The `(C-Br)` bond in the case of `7-` bromo `-1,3,5-` cycloheptatriene is broken easily because the intermidate carbocation formed is very stable (aromatic as it contains `(4n + 2) pi overline(e)`, i.e, follows Huckel's rule), while it does not break easily in the case of `5-` bromo `-1,3-` cycloopentandiene becuase carbocation formed here, is higly unstable as it is anti-aromatic i.e., does not follow Huckel's rule (It contains `4pi` electrons.)