## Chemistry: Atoms First (2nd Edition)

$[OH^-] = 1.259\times 10^{- 12}M$ $[H_3O^+] = 7.943\times 10^{- 3}M$ pOH = 11.9 - Gastric juice is acidic.
1. Calculate the hydronium concentration: $[H_3O^+] = 10^{-pH}$ $[H_3O^+] = 10^{- 2.1}$ $[H_3O^+] = 7.943 \times 10^{- 3}$ 2. Calculate the pOH, then the hydroxide ion concentration: pH + pOH = 14 2.1 + pOH = 14 pOH = 11.9 $[OH^-] = 10^{-pOH}$ $[OH^-] = 10^{- 11.9}$ $[OH^-] = 1.259 \times 10^{- 12}$ - Since $[H_3O^+] > [OH^-]$, the solution is acidic.