Which among the following is the strongest acid?

$A$ and $B$ are isomers. Product $B$ is: (Dewar's Benzene is $A$)

The product obtained in the reaction of benzene with chlorine in the presence of ultraviolet light is ...... .

What products are formed when the following compound is treated with $Br_2$ in the presence of $FeBr_3$?

Which order is correct for the decreasing reactivity to ring monobromination of the following compounds: $C_6H_5CH_3$ $(I)$,$C_6H_5COOH$ $(II)$,$C_6H_6$ $(III)$,and $C_6H_5NO_2$ $(IV)$?

What is the major product of the following reaction?
$1,4-dichlorocyclohexa-1,4-diene \xrightarrow{Na, \text{dry ether}} ?$