Answer:
600 mL of ethyl alcohol is the solvent.
Step-by-step explanation:
The solute is always lesser in amount than the solvent. Here we have 150 ml water and 600 ml ethyl alcohol. So the 150 ml water (lesser in amount) is the solute and 600 ml ethyl alcohol is the solvent. The solute gets dissolved in the solvent to form the solution. The solvent is the one that dissolves the solute to form a homogeneous solution.