When the aromatic hydrocarbon naphthalene reacts with nitric and sulfuric acids, two compounds containing one nitro group are formed. What are the structures of these two compounds?

1 Answer
Dec 27, 2014

The two compounds are 1-nitronaphthalene and 2-nitronaphthalene.

The nitration of naphthalene is an electrophilic aromatic substitution.

It involves the attack of nitronium ion, NO₂⁺, on the aromatic system.

Attack at C-1

Nitration at C-1 produces a carbocation that has 7 resonance contributors.


Four of these ( 1, 2, 6, and 7) preserve the aromaticity (six π electrons) of the second ring.

Attack at C-2

Nitration at C-2 produces a carbocation that has 6 resonance contributors.


Two of these (1 and 6) preserve the aromaticity of the second ring.

So attack at C-1 is favoured, because it forms the most stable intermediate.

The major product is 1-nitronaphthalene. The minor product is 2-nitronaphthalene.