The vapour pressure of a solution (made by dissolving a solute in a solvent) is ____________ that of the pure solvent?

Related Mcqs:

1. The vapor pressure of the solvent decreased by 10 mm Hg, when a non-volatile solute was added to the solvent. The mole fraction of the solute in the solution is 0.2. What should be the mole fraction of the solvent, if the decrease in vapor pressure of the solvent is required to be 20 mm Hg ?

   A. 0.2
   B. 0.1
   C. 0.4
   D. 0.6

2. A very dilute solution is prepared by dissolving ‘x1’ mole of solute in ‘x2’ mole of a solvent. The mole fraction of solute is approximately equal to_________________?

   A. x1/x2
   B. x2/x1
   C. 1 – (x1/x2)
   D. 1/x2

3. A solution is made by dissolving 1 kilo mole of solute in 2000 kg of solvent. The molality of the solution is_________________?

   A. 2
   B. 1
   C. 0.5
   D. 0.05

4. Osmotic pressure exerted by a solution prepared by dissolving one gram mole of a solute in 22.4 litres of a solvent at 0°C will be _______________ atmosphere?

   A. 0.5
   B. 1
   C. 1.5
   D. 2

5. Dissolving a solute in a solvent does not change its________________?

   A. Specific heat
   B. Vapour pressure
   C. Viscosity
   D. None of these

6. A vessel of volume 1000 m3 contains air which is saturated with water vapour. The total pressure and temperature are 100 kPa and 20°C respectively. Assuming that the vapour pressure of water at 20°C is 2.34 kPa, the amount of water vapour (in kg) in the vessel is approximately ?

   A. 17
   B. 20
   C. 25
   D. 34

7. At 100°C, water and methylcyclohexane both have vapour pressures of 1 atm. Also at 100°C, the latent heats of vaporisation of these compounds are 40.63 kJ/mole for water and 31.55 kJ/mole for methylcyclohexane. The vapour pressure of water at 150°C is 4.69 atm. At 150°C, the vapour pressure of methylcyclohexane would be expected to be_________________?

   A. Significantly less than 4.69 atm
   B. Nearly equal to 4.69 atm
   C. Significantly more than 4.69 atm
   D. Indeterminate due to lack of data

8. Saturated solution of benzene in water is in equilibrium with a mixture of air and vapours of benzene and water at room temperature and pressure. Mole fraction of benzene in liquid is xB and the vapour pressures of benzene and water at these conditions are pv B and pv w respectively. The partial pressure of benzene in air-vapour mixture is_________________?

   A. PvB
   B. xB.PvB
   C. (Patm – Pvw)xB
   D. xB.Patm

9. Osmotic pressure of a dilute solution of a non volatile solute in a solvent obeying Raoult’s law is proportional to the_____________?

   A. Temperature
   B. Volume of solution
   C. Moles of non-volatile solute
   D. None of these

10. Vapor pressure of a solution is proportional to (where, Sv and St are mole fraction of solvent and solute respectively) ?

    A. Sv
    B. 1/St
    C. St
    D. 1/Sv