Question

The number of distinct products formed after the nitration of tetralone in the presence of \(HNO_3\) and \(H_2SO_4\) is _ _ _. (in integer)

Hint:

For substituted fused aromatic systems, count only non-equivalent aromatic positions carrying hydrogen to determine the number of possible monosubstitution products.

Answer 1

Correct Answer: 4

Step 1: Identify the reaction.
Nitration using \(HNO_3/H_2SO_4\) is an electrophilic aromatic substitution reaction.
The active electrophile is the nitronium ion:
\[ NO_2^+ \]

Step 2: Identify the aromatic ring in tetralone.
Tetralone contains a benzene ring fused with a cyclohexanone ring.
Nitration occurs on the aromatic benzene ring.

Step 3: Count the available aromatic positions.
In tetralone, two aromatic carbons are fused with the saturated ring and do not carry hydrogen.
The remaining four aromatic carbons carry hydrogen atoms and can undergo substitution.

Step 4: Check symmetry of tetralone.
Because the fused cyclohexanone ring contains a carbonyl group on one side, the molecule is not symmetric with respect to all aromatic positions.
Therefore, the four aromatic substitution positions are not equivalent.

Step 5: Consider mononitration products.
Each non-equivalent aromatic hydrogen can be replaced by a nitro group.
Thus, nitration can give four distinct mononitro products.

Step 6: Confirm distinctness of products.
Since the aromatic positions are chemically non-equivalent due to the fused carbonyl-containing ring, substitution at each position gives a different constitutional isomer.

Step 7: Final conclusion.
Therefore, the number of distinct nitration products is
\[ \boxed{4} \]