Answer:
1.67mL of 95% ethyl alcohol are required to dissolve completely the sulfanilamide
Explanation:
Solubility is defined as the amount of substance that a determined amount of solvent can dissolve
As you can see, 95% ethyl alcohol at 78°C can dissolve 180mg of sulfanilamide per mililiter. That means solubility is 180mg/mL = 0.180g/mL.
As you want to dissolve 0.3g, you require:
0.3g * (1mL / 0.180g) =
1.67mL of 95% ethyl alcohol are required to dissolve completely the sulfanilamide
