## Chemistry: Atoms First (2nd Edition)

$[HI] = 3.162 \times 10^{- 3}M$
1. Calculate the hydronium concentration: $[H_3O^+] = 10^{-pH}$ $[H_3O^+] = 10^{- 2.5}$ $[H_3O^+] = 3.162 \times 10^{- 3}M$ 2. Since $HI$ is a strong acid: $[HI] = [H_3O^+] = 3.162 \times 10^{- 3}M$