Chemistry PLS HELP

Question

Calculate [H3O+] for a 8.78×10−3 M HBr solution.

Answer 1

HBr is a strong acid. So it will ionize completely.

HBr + H₂O H₃O⁺ + Br^-

So, [HBr] = [H₃O⁺] = 8.78×10−3 M