Answer:

Raoult's law states that the vapor pressure of a solvent above a solution is equal to the vapor pressure of the pure solvent at the same temperature scaled by the mole fraction of the solvent present: Psolution=χsolventPosolvent.
Answer: The strange liquid would float to the top of a cup of water.
Explanation:
Density = Mass/Volume
Strange Liquid Density = 70g/84mL
Strange Liquid Density = 0.833g/mL
Density of water in g/mL = 1 g/mL
Strange Liquid Density < Water Density
A substance with a lower density would be suspended above a substance with a higher density.
Since the density of the strange liquid is less than that of water, it would float to the top of a cup of water.
Cs is more reactive than Sr
In order to do this you must add up all of the molar masses of each compound and then judge accordingly.