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: Name the reaction.
Mixing $HNO_3$ with $H_2SO_4$ makes the nitronium ion $NO_2^+$, which does electrophilic aromatic substitution on the benzene ring of tetralone.

Step 2: Find the open positions.
Two of the six ring carbons are fused to the saturated ring and carry no hydrogen. That leaves four ring carbons that each bear a hydrogen and can be nitrated.

Step 3: Check for symmetry.
The fused ring carries a carbonyl on one side, so the molecule is not symmetric. The four open positions are all chemically different from one another.

Step 4: Count distinct products.
Replacing the hydrogen at each of the four non-equivalent positions gives four different mononitro isomers.

Step 5: Answer.
\[ \boxed{4} \]