As, the temperature decreased from 40.0 °C to 0.0 °C an amount will be recrystallized and precipitated as solid crystals in the water (51.0 g - 14.0 g = 37.0 g) and 14.0 g will be dissolved in water.
Explanation:
Firstly, we must mention that:
The solubility of KNO₃ per 100.0 g of water at 40.0 °C = 63.0 g.
The solubility of KNO₃ per 100.0 g of water at 0.0 °C = 14.0 g.
So, at 40.0 °C, 51.0 g of KNO₃ will be completely dissolved in water.
<em>As, the temperature decreased from 40.0 °C to 0.0 °C an amount will be recrystallized and precipitated as solid crystals in the water (51.0 g - 14.0 g = 37.0 g) and 14.0 g will be dissolved in water.</em>