At 40 °C, the ion-product constant of water is Kw=2.92×10−14. A student dissolves 5.00 g of KOH (molar mass 56.11 g mol−1) in enough water to make 750.0 mL of solution at this temperature. Assuming complete dissociation, what is the pH of the solution at 40 °C?
a) 13.08
b) 12.49
c) 12.61
d) 12.95