A mole of HBr, a strong acid, is made up to a liter of solution with pure water. At equilibrium...

(a) [H+] = 1M
(b) [H+] = 0M
(c) pH = 0
(d) both a & c
(e) we cannot say without exact pKa of hydrobromic acid.

2 answers

So you have (HBr) = 1 mole/L = 1M
Since HBr is a strong acid, (H^+) must be 1 M also.
Thank you!!