How do you determine the chemical formula of the barium halide salt and identity of the halide salt?Need help!?

A 0.158g sample of a salt, comprised of barium and one of the halide ions, was dissolved in water, and an excess of sulfuric acid was added to form barium sulfate, BaSO4. After filtering and drying the solid BaSO4 weighed 0.124g. WHat's the chemical formula of the barium halide salt and identity of the halide???