a. Compare the following reaction.

Explanation

a.
b. Oxidation and reduction of anthracene at 9 and 10 positons leave two benzene rings intact with a total resonace energy of `(2xx150.4) = 300.8 kJ mol^(-1)` for isolated rings. Attack at any other positon in the outer rings would leave a naphtalene ring intact, having only `255 kJ mol^(-1)` (R.E. of napthalene). More the resonance energy, more stable is the compound. Therefore, positons 9 and 10 in athrancene are more reactive.