Final answer:
The optimal reagents for a reaction with ROOR, heat would be Hydrobromic acid (HBr) for a free radical addition to alkenes. Sodium borohydride and sulfuric acid are not appropriate for this reaction. Peroxide is already included in the reaction conditions.
Step-by-step explanation:
The question asks to select the best reagents for the reaction shown: ROOR, heat. This typically indicates a radical reaction, such as the free radical addition of HBr to alkenes in the presence of peroxide (ROOR). Therefore, the correct answer is Hydrobromic acid (HBr), which, when used with peroxides, can lead to anti-Markovnikov addition to alkenes via a free radical mechanism.
Using sulfuric acid (H2SO4), heat will most likely lead to a different reaction path, such as the dehydration of alcohols to alkenes. Sodium borohydride (NaBH4) is a reducing agent and would not be appropriate for this kind of radical addition reaction. Since peroxide (ROOR) is already listed as part of the reaction conditions, adding it as a reagent would be redundant.
Hydrogen bromide can be prepared using phosphoric acid (H3PO4) because it is a weaker oxidizing agent than sulfuric acid, preventing the oxidation of bromide ions to bromine.