The function of anhydrous $AlCl_3$ in the Friedel-Crafts reaction is to

Consider the following sequence of reactions. In $Z$,the number of $sp^3$ carbons is $a$ and $sp^2$ carbons is $b$. The value of $(a+b)$ is:
$CH_3CH_2CH_2CH_2Br$ $\xrightarrow[\text{dry ether}]{Na} X$ $\xrightarrow[\text{10-20 atm}]{\text{Cr}_2\text{O}_3 / 773 \text{ K}} Y$ $\xrightarrow[\text{anhy. AlCl}_3]{\text{CH}_3\text{COCl}} Z$

The electrophilic aromatic substitution proceeds through a

In the given compounds,the correct order of reactivity in electrophilic substitution reactions will be:

In the conversion of $A$ to $B$,the electrophile involved is:

Statement-$I$: Benzene gives Friedel-Crafts reaction.
Statement-$II$: All substituted benzenes give Friedel-Crafts reaction.
Choose the correct statement: