Same chapter3 marksDifficulty: Medium
Calculate the molality of a solution containing 18 g of glucose in 500 g of water. (Molar mass of glucose = 180 g)
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3 marksDifficulty: Medium
State Raoult's law and distinguish between positive and negative deviations from it.
Original Khojo Papers practice question — not from a past board paper.
Answer
Raoult's law states that for a solution of volatile liquids the partial vapour pressure of each component is the product of its mole fraction and its vapour pressure in the pure state. A positive deviation shows a higher vapour pressure than predicted, because the interactions between unlike molecules are weaker than between like ones, as in ethanol and acetone. A negative deviation shows a lower vapour pressure, the unlike interactions being stronger, as in chloroform and acetone.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
A positive deviation gives a minimum-boiling azeotrope and a negative deviation a maximum-boiling one.
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