Question

What will be the mass of a non-volatile solute (molar
mass 40 g mol-') which should be dissolved in 114 g
octane to reduce its vapour pressure to 80%?​

Answer 1

Answer:

Let the vapour pressure of pure octane be p10. Then, the vapour pressure of the octane after dissolving the non-volatile solute is 80/100 p10 = 0.8 p10. Hence, the required mass of the solute is

8g