Question

What is the pH of a 3.3 × 10⁻⁶ M HBr solution?

Answer 1

\(\text{HBr}_{(aq)}+\text{H}_2\text{O}_{(l)}⇌\text{H}_3\text{O}^+_{(aq)}+\text{Br}^-_{(aq)} \)

Since HBr is a strong acid, it dissociates fully and you do not need to set up a RICE table. You can just use the formula

\(pH=-log[\text{H}_3\text{O}^+]\)

To find \([\text{H}_3\text{O}^+]\), it is fairly simple here. If you go back to the equation above, since HBr and H3O+ have the same stoichiometric ratio, \([\text{H}_3\text{O}^+]=3.3 \times 10^6\). Now you can plug the rest into your calculator.