The pressure imposed by a gas on a liquid (or solid) in a closed system at a certain temperature is known as vapour pressure. When liquid molecules try to exit the surface of the liquid through evaporation, they are subjected to upward pressure. Simply put, it is the pressure exerted by the vapour existing above the liquid surface. Raoult’s law describes how adding a solute lowers the vapour pressure. Now let’s get into the meat of the matter.
The mass of a non-volatile solute of molar mass 40g/mol that should be dissolved in 114g of octane to lower its vapour pressure by 20% is:
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Principal, Babu Daudayal SVM, Mathura