The solubility of potassium nitrate KNO3 in water at room temperature 25C is approximately 37 grams per 100 grams of water. This means that 37 grams of KNO3 can dissolve in 100 grams of water at 25C.The solubility of sodium chloride NaCl in water at room temperature 25C is approximately 36 grams per 100 grams of water. This means that 36 grams of NaCl can dissolve in 100 grams of water at 25C.Comparing the solubility of KNO3 and NaCl at 25C, potassium nitrate is slightly more soluble in water than sodium chloride.