Simon had a porch faucet that leaked 2.5 L of water on his front porch and froze into a puddle. He sprinkled 100.0 g of NaCl on the ice, and he was pleased to see it melt. However, it was still winter in Minnesota. At what temperature will the puddle refreeze? (Kf for water is 1.86 °C/m, and the density of water at 0 °C = 0.99987 g/mL)