What is produced when benzene is alkylated with $n$-propyl chloride in the presence of anhydrous $AlCl_3$?

The main product of the following reaction will be

What are $X$ and $Y$ in the following reaction sequence?
$CH_3(CH_2)_5CH_3 \stackrel{X}{\longrightarrow} C_7H_8 \stackrel{Br_2}{\Delta} Y$

Given below are two statements,one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$ : Benzene is more stable than hypothetical cyclohexatriene.
Reason $R$ : The delocalized $\pi$ electron cloud is attracted more strongly by nuclei of carbon atoms.
In the light of the above statements,choose the correct answer from the options given below:

Benzene + $CH_3CH_2CH_2CH_2Cl \xrightarrow{AlCl_3}$ hydrocarbon $(X)$. The major product $X$ is:

What are the various steps of electrophilic substitution of benzene?