Advertisements
Advertisements
प्रश्न
Give two points to explain why vapour pressure of solvent is lowered by dissolving nonvolatile solute into it.
Advertisements
उत्तर
- Vapour pressure of a liquid depends on the ease with which the molecules escape from the surface of liquid. When nonvolatile solute is dissolved in a solvent, some of the surface molecules of solvent are replaced by nonvolatile solute molecules. These solute molecules do not contribute to vapour above the solution.
- Thus, the number of solvent molecules available for vaporization per unit surface area of a solution is less than the number at the surface of pure solvent. As a result the solvent molecules at the surface of solution vaporize at a slower rate than pure solvent. This results in lowering of vapour pressure.
संबंधित प्रश्न
Answer the following.
How vapour pressure lowering is related to a rise in the boiling point of solution?
Answer the following.
Why vapour pressure of a solvent is lowered by dissolving a nonvolatile solute into it?
The following solution/solvent has maximum vapour pressure _______.
According to Raoult’s law, relative lowering of vapour pressure of solution containing dissolved nonvolatile solute _______.
Write the expression for relative lowering of vapour pressure.
The vapour pressure of a pure liquid is 0.043 bar at a certain temperature. When a nonvolatile solute is dissolved into it, the vapour pressure of the solution is found to be 0.041 bar. What is the relative lowering of vapour pressure?
For a very dilute solution, the osmotic pressure is given by π = n2RT/V where V is the volume in L containing n2 moles of nonvolatile solute. Establish the equation for molar mass of solute.
The vapour pressure of pure solvent and solution are 120 mm Hg and 108 mm Hg respectively. The mole fraction of the solvent in the solution is ____________.
Which of the following is CORRECT for a solution containing non-volatile solute in it?
In an experiment, 1 g of a non-volatile solute was dissolved in 100 g of acetone (molar mass = 58 g mol−1) at 298 K. The vapour pressure of the solution was found to be 192.5 mm Hg. The molecular weight of the solute is (vapour pressure of acetone = 195 mm Hg) ____________ g mol−1.
Which of the following is CORRECT statement?
According to Raoult's law, relative lowering of vapour pressure for a solution containing a nonvolatile solute is equal to ____________.
Relative lowering in vapour pressure of a solution containing non-volatile solute is the ratio of ____________.
Which of the following is INCORRECT expression in terms of vapour pressure of pure solvent `("P"_1^0)` and that of solution (P)?
The vapour pressure of water at 20°C is 17 mm Hg. The vapour pressure of solution containing 2.8 g urea in 50 g of water is ____________.
Which of the following changes will cause increase in vapour pressure of 1 molal aqueous KI solution at same temperature?
What will be the molar mass of solute if vapour pressure of pure benzene is 450 mm Hg when 1.5 g of non-volatile solute is added to 30 g of benzene?
(Vapour pressure of solution= 400 mm Hg, Atomic mass C = 12, H = 1)
Identify the correct statement from the following:
12 g of a nonvolatile solute dissolved in 108 g of water produces the relative lowering of vapour pressure of 0.1. The molecular mass of the solute is ______.
The vapour pressure of 100 g of water reduces from 17.53 mm to 17.22 mm when 17.10 g, of substance X is dissolved in it. Substance X can be ______.
