Which shows equilibrium between solute and solvent? I'm stumped.

a. 2 M CaCl2
b. 1 g Na2CO3 & 100 mL H2O
c. 2 mL methanol & 4 mL hexane
d. 1 mL H2O & 3 mL ethanol

1 answer

I was stumped, also, but after thinking long and hard I believe the answer is C. Choices a, b, and d are cases in which the solute is completely soluble in the solvent. Methanol and hexane are not miscible so there is an equilibrium set up between the two for the solubility of one in the other.