How many products can be expected if naphthalene is subjected to any type of mono aromatic electrophilic substitution reactions.

however (in contrast to benzene), the positions in the naphthalene nucleus are not all equivalent, substitution in naphthalene can lead to two isomeric monosubstitution products. In naphthalene, electrophilic substitution can occur at carbon-1 or at carbon-2. The carbocation formed by the attack of electrophile at 1-position of naphthalene is much more stabilize by resonance since it has four contributing structures in which aromatic character is retained in one of the ring