Calculate either [ H 3 O + ] or [ OH − ] for each of the solutions at 25 °C . Solution A: [ OH − ] = 2.59 × 10 − 7 M Solution A: [ H 3 O + ] = M Solution B: [ H 3 O + ] = 9.57 × 10 − 9 M Solution B: [ OH − ] = M Solution C: [ H 3 O + ] = 0.000691 M Solution C: [ OH − ] = M Which of these solutions are basic at 25 °C ? Solution A: [ OH − ] = 2.59 × 10 − 7 M Solution B: [ H 3 O + ] = 9.57 × 10 − 9 M Solution C: [ H 3 O + ] = 0.000691 M