Identifying the acid, what is the formula for hydrobromic acid?

The formula for hydrobromic acid is HBr. This compound consists of hydrogen (H) and bromine (Br) atoms, where one hydrogen atom is bonded to one bromine atom. In naming binary acids, which are composed of hydrogen and one other nonmetalloid element, the prefix "hydro-" is used, followed by the root name of the nonmetal, and the suffix "-ic." Thus, hydrobromic acid comes from hydrogen and bromine, resulting in HBr.

In the context of the other options:

H2Br would imply two hydrogen atoms with one bromine, which does not accurately represent hydrobromic acid as it would not align with the expected behavior of acids in solutions. BrH, while it does contain the correct elements, does not follow the conventional acid notation. H3Br2 suggests a compound that would contain three hydrogen atoms and two bromine atoms, which does not exist as a simple binary acid. Therefore, the formula HBr correctly represents hydrobromic acid, aligning with both nomenclature rules and the actual composition of the acid.