After ozonolysis of benzene (not hydrolysis),the product is

Identify the product $X$ obtained in the following reaction:
$CH_{3}-(CH_{2})_{4}-CH_{3} \xrightarrow{Cr_{2}O_{3}, 773 \ K, 10-20 \ atm} X$

The number of possible aromatic benzenoid isomers for $C_6H_4Cl_2$ are

When benzene is treated with excess of $Cl_2$ in the presence of $FeCl_3$ (or $I_2$ as a carrier),the end product is:

Given below are two statements $:$
Statement $(I) :$ On nitration of $m-$xylene with $HNO_3, H_2SO_4$ followed by oxidation,$4-$nitrobenzene$-1, 3-$dicarboxylic acid is obtained as the major product.
Statement $(II) :$ $-CH_3$ group is $o/p-$directing while $-NO_2$ group is $m-$directing group.
In the light of the above statements,choose the correct answer from the options given below $:$

Answer the following questions: Which catalyst is used in the Friedel-Crafts alkylation reaction? And what is its function?