Hydrogen fluoride is used:

a. in the manufacture of steel.
b. in the synthesis of cryolite for aluminum production.
c. as an oxidizing agent.
d. as a disinfectant.
e. as a mouthwash.

The correct answer is option B)

in the synthesis of cryolite for aluminum production.

Explanation:

Hydrogen fluoride (HF) is used in synthesis of cryolite for aluminum production.

HF is a gas that dissolves in water to form hydrofluoric acid. However, HF also react with halogenated alkanes like trichloromethane CHCl3 to form organofluorine compounds that serves as precursors in the synthesis of cryolite, an Ore from which aluminum is produced