Toluene reacts with a halogen in the presence of iron (III) chloride giving ortho and para halo compounds. What is the reaction called? 

Electrophilic substitution reaction

The correct answer is option 1. Electrophilic substitution reaction.

In an electrophilic substitution reaction, an electrophile (a positively charged or electron-deficient species) attacks an electron-rich aromatic compound, such as toluene. The electrophile then reacts with a hydrogen atom on the aromatic ring, forming a new bond and displacing the hydrogen atom. The halogen atom from the halogen molecule then replaces the hydrogen atom.

In the reaction of toluene with halogen in the presence of iron (III) chloride, the halogen molecule \((Cl_2)\) is first activated by the iron (III) chloride to form an electrophile, \(Cl^+\). The \(Cl^+\) then attacks the electron-rich benzene ring of toluene, forming a new bond and displacing a hydrogen atom. The halogen atom from the halogen molecule then replaces the hydrogen atom.

The product of this reaction is a mixture of ortho and para halo compounds. This is because the \(-CH_3\) group on toluene is an ortho/para director, which means that it directs the incoming electrophile to the ortho and para positions on the benzene ring.

Free radical addition reactions and nucleophilic substitution reactions do not occur in this reaction. In a free radical addition reaction, a free radical (a neutral species with an unpaired electron) adds to an unsaturated compound. In a nucleophilic substitution reaction, a nucleophile (a negatively charged or electron-rich species) attacks an electrophile and replaces a leaving group. Neither of these reactions occur in the reaction of toluene with halogen in the presence of iron (III) chloride.