I think this reaction is forming 2,4,6- trinitrotoluene from benzene, since the product is not mentioned. Following are the steps to convert Benzene to 2,4,6 trinitrotoluene .

Step 1: Conversion of Benzene to Toluene .

Benzene can be converted to toluene by Friedel Craft Alkylation of benzene . In this reaction reagent AlCl₃ and Ch3Cl is used . Electrophile CH³⁺ is produced which attached on carbon of benzene and formation of Toluene and HCl occur.

$Benzene \frac{AlCl3}{Ch3Cl}> Toulene + HCl$

Step 2 : Conversion of Toluene to dinitrotoluene.

Dinitritoluene is prepared from toluene by Nitration . This reaction uses Electrophilic substitution mechanism . The reagents used are HNO₃ and H₂SO₄ at room temperature . These reagents produces NO₂⁺ ( nitronium ion ), a electrophile which attacks on C2 and C4 Carbon atoms of Toluene.

Toluene $Tolune \frac{HNO3 -H2SO4}{30-40 degree C} -> 2,4- dinitrotoluene$

Step 3) Conversion of Dinitro toluene to trinitrotoluene.

This reaction is extended nitration of toluene . Further nitration is done in extreme condition . The temperature of reaction is increased to 90- 100 ⁰ C . Due to which there is more production of NO²⁺ ion occurs from HNO₃ -H₂SO₄ and they attack on C6 carbon atom of dinitrotoluene which forms 2,4,6- trinitrotoluene.

Dinitrotoluene $2,4 -dinitrotoluene \frac{fuming HNO3-H2So4}{90-100 C} -> 2,4,6-trinitrotoluene.$

So over all reaction uses three reagents in order :

$Benzene \frac{AlCl3}{CH3Cl} -> Toluene \frac{HNO3-H2So4}{room temp} -> 2,4-dinitrotoluene \frac{Fuming HNO3 -H2SO4}{Heating at 90-100 C} -> 2,4,6-trinitrotoluene .$