To determine how much sodium chloride will not dissolve, we need to know the solubility of NaCl at 80°C. At 80°C, the solubility of NaCl in water is 37.8 g/100 mL.
We have 100 grams of water which is equivalent to 100/1000 = 0.1 L of water.
The maximum amount of NaCl that can dissolve in 0.1 L of water at 80°C is:
37.8 g/100 mL x 0.1 L = 0.378 x 10 g = 3.78 g
Since we have 50 grams of NaCl, which is greater than the maximum amount that can dissolve, the excess amount that will not dissolve is:
50 g - 3.78 g = 46.22 g
Therefore, 46.22 grams of NaCl will not dissolve.