Advertisements
Advertisements
Question
State Raoult law and obtain the expression for lowering of vapour pressure when the nonvolatile solute is dissolved Insolvent.
Advertisements
Solution
In an ideal solution, the vapour pressure of the solution is decreased when a non-volatile solute is dissolved in a solvent. The magnitude of decrease in the vapour pressure of the solution depends on the amount of solute added.
Let us consider the solution with the following features.
Mole fraction of the solvent = xA
Mole fraction of the solute = xB
Vapour pressure of the pure solvent = P°A
Vapour pressure of solution = P
As the solute is nonvolatile, the vapour pressure of the solution is only due to the solvent.
Therefore, the vapour pressure of the solution (P) will be equal to the vapour pressure of the solvent (PA) over the solution.
i.e., P = PA
According to Raoult’s law, the vapour pressure of solvent over the solution is equal to the product or its vapour pressure in a pure state and its mole fraction.
PA = P°A xA or
P = P°A xA
APPEARS IN
RELATED QUESTIONS
Heptane and octane form an ideal solution. At 373 K, the vapour pressures of the two liquid components are 105.2 kPa and 46.8 kPa respectively. What will be the vapour pressure of a mixture of 26.0 g of heptane and 35 g of octane?
Suggest the most important type of intermolecular attractive interaction in the following pair.
Acetonitrile (CH3CN) and acetone (C3H6O)
Which solution has the lower freezing point? 10 g of methanol (CH3OH) in 100g g of water (or) 20 g of ethanol (C2H5OH) in 200 g of water.
The observed depression in the freezing point of water for a particular solution is 0.093°C calculate the concentration of the solution in molality. Given that molal depression constant for water is 1.86 K Kg mol-1.
Concentration terms such as mass percentage, ppm, mole fraction and molality are independent of temperature, however molarity is a function of temperature. Explain.
What is “semi permeable membrane”?
Upon increase in pressure for dissociation N2O4 into NO2, equilibrium shift towards
Dissociation constant and molar conductance of an acetic acid solution are 1.78 × 10–5 mol L–1 and 48.15 S cm–2 mol–1 respectively. The conductivity of the solution is (considering molar conductance at infinite dilution is 390.5 S cm–2 mol–1)
On increase in pressure for dissociation ofN2O4 into NO2, equilibrium shift towards
What type of deviation from Roult’s Law is expected when phenol and aniline are mixed with each other? What change in the net volume of the mixture is expected? Graphically represent the deviation.
