Answer:
NaNO₃.
Step-by-step explanation:
- From the attached figure, the solubility of the different salts is:
It is 90 g per 100 g water.
It is 110 g per 100 g water.
It is about 20 g per 100 g water.
It is about 40 g per 100 g water.
So, the most soluble salt at 50°C is NaNO₃.