Final answer:
The chemical potential of benzene at 25°C decreases when a solute is present at a mole fraction of 0.10, following Raoult's Law.
Step-by-step explanation:
The chemical potential of benzene at 25°C when a solute is present with a mole fraction x2 = 0.10 will decrease. This is in accordance with Raoult's Law, which states that the presence of a solute lowers the chemical potential of the solvent. The decrease in chemical potential is directly proportional to the mole fraction of the solute in an ideal solution. Therefore, the correct answer is (c) Decreases.