The aromatic carbocation among the following is ____________

Two isomeric compounds $\mathrm{I}$ and $\mathrm{II}$ are heated with $\mathrm{HBr}$.

The products obtained are

For the transformation

the reagent used is:

The reaction

is known as:

The products $\mathrm{X}$ and $\mathrm{Y}$ in the following reaction sequence are :

The major product of the following reaction is

In the following reaction sequence

$\mathrm{X}$ and $\mathrm{Y}$ are, respectively