Explain with the aid of equations and chemical structures why nitration of Naphthalene gives only one product?

Nitration of naphthalene involves the substitution of a nitro group (-NO2) for a hydrogen atom on the aromatic ring. Naphthalene has two equivalent positions for nitration, as shown in the following chemical structure:

```
H H
| |
H--C--C--C--C--H
| |
H H
```

The two possible products of nitration are 1-nitronaphthalene and 2-nitronaphthalene. However, due to the symmetrical nature of the naphthalene molecule, both positions are equivalent and the same product is obtained regardless of which position is nitrated. This is because the two positions are related by a symmetry operation (rotation by 180 degrees), as shown in the following chemical structure:

```
H H
| |
H--C--C--C--C--H
| |
H H
```

Therefore, nitration of naphthalene gives only one product, which is a mixture of 1-nitronaphthalene and 2-nitronaphthalene. This can be represented by the following equation:

C10H8 + HNO3 -> C10H7NO2 + H2O

where C10H7NO2 represents the mixture of 1-nitronaphthalene and 2-nitronaphthalene.