Final answer:
The number of isomers possible for the aromatic compound C7H9N that forms benzyl alcohol through a reaction is six, due to the arrangement of substituents on the benzene ring and the equivalent ortho, meta, and para positions.
Step-by-step explanation:
The question involves the determination of the number of possible isomers for an aromatic compound with the formula C₇H₉N that produces benzyl alcohol and nitrogen gas when reacting with NaNO₂ / HCl at 0°C. Since the reaction forms benzyl alcohol, the N in the original compound C₇H₉N must be in the form of a benzylamine group, indicating that the compound is a substituted benzene. Based on this formula, we can deduce that there must be a benzene ring with a CH₂N group and one additional H somewhere on the ring.
The benzene ring has six carbon atoms with alternating single and double bonds. Substituents on benzene can lead to the formation of structural isomers. These isomers include ortho, meta, and para positions relative to the benzylamine group. For C₇H₉N, the substituents could be alkyl or additional amino groups, which introduces the possibility for several structural isomers.
Considering the valence bond theory with resonance structures and delocalization within the benzene ring, various positions for the substituents lead to different isomers. Therefore, the number of isomers for the compound in question is six, as the question provides. To enumerate them, we can arrange the additional H in the six possible positions relative to the benzylamine group, keeping in mind that some positions are equivalent (ortho, meta, para).