Define azeotropes. What type of azeotrope is formed by positive deviation from Raoult's law ? Give an example.
What is meant by positive deviations from Raoult's law? Give an example. What is the sign of ∆mixH for positive deviation?
The vapour pressure of water is 12.3 kPa at 300 K. Calculate vapour pressure of 1 molal solution of a non-volatile solute in it.
A solution containing 30 g of non-volatile solute exactly in 90 g of water has a vapour pressure of 2.8 kPa at 298 K. Further, 18 g of water is then added to the solution and the new vapour pressure becomes 2.9 kPa at 298 K. Calculate:
(1) molar mass of the solute
(2) vapour pressure of water at 298 K.
An aqueous solution of 2% non-volatile solute exerts a pressure of 1.004 bar at the normal boiling point of the solvent. What is the molar mass of the solute?
What is meant by positive and negative deviations from Raoult's law and how is the sign of ΔsolH related to positive and negative deviations from Raoult's law?
Calculate the mass of a non-volatile solute (molar mass 40 g mol−1) which should be dissolved in 114 g octane to reduce its vapour pressure to 80%.
Vapour pressure of pure water at 298 K is 23.8 mm Hg. 50 g of urea (NH2CONH2) is dissolved in 850 g of water. Calculate the vapour pressure of water for this solution and its relative lowering.
Why does a solution containing non-volatile solute have higher boiling point than the pure solvent ?
Vapour pressure of pure acetone and chloroform at 328 K are 741.8 mm Hg and 632.8 mm Hg respectively. Assuming that they form ideal solution over the entire range of composition, plot ptotal’pchloroform’ and pacetone as a function of xacetone. The experimental data observed for different compositions of mixture is.
|pacetone /mm Hg||0||54.9||110.1||202.4||322.7||405.9||454.1||521.1|