--%>
Assignment Help - homework help

Explain solid in liquid solutions.

The French chemist Francois Marie Raoult (1886) carried out a series of experiments to study the vapour pressure of a number of binary solutions. On the basis of the results of the experiments, he proposed a generalization called Raoult's law which states that, 

The vapour pressure of a solution containing non-volatile solute is directly proportional to the mole fraction of the solvent.

In case of solution containing two components A (volatile solvent) and B (non-volatile solute) the vapour pressure of solution is given as

[Vapour pressure of solution] = [vapour pressure of solvent in solution (pA) ∝ [mole fraction of solvent (xA)]
                                                  
Or pA ∝ xA
                                                
Or, pA = kxA

Where k is proportionality constant.

For pure liquid, xA = 1 then k becomes equal to be vapour pressure of the pure solvent which is denoted by pA°.

Thus, pA = pA°xA                                            (i)

Or psolution × mole fraction of solvent.

For solutions obeying Raoult's law at all concentrations its vapour pressure would vary linearly from zero to the vapour pressure of pure solvent.

If mole fraction of solute is sB, then

xA + xB = 1 or xA = 1 - xB                             (ii)

From eqns. (i) and (ii),

pA = pA°(1 - xB) = pA° - pA°xB

Or, pA° - pA = pA°xB

2263_solids on liquids.png

   Related Questions in Chemistry

  • Q : Molarity of pure water Choose the right

    Choose the right answer from following. The molarity of pure water is: (a) 55.6 (b) 5.56 (c)100 (d)18

    		•
  • Q : What do you mean by the term enzymes

    What do you mean by the term enzymes? Briefly illustrate it.

    		•
  • Q : Question based on vapour pressure While

    While a substance is dissolved in a solvent, the vapour pressure of the solvent is decreased. This results in: (a) An increase in the boiling point of the solution (b) A decrease in the boiling point of solvent (c) The solution having a higher freezing point than

    		•
  • Q : Question based on mole concept Help me

    Help me to solve this Question. The number of moles of SO2Cl2 in 13.5 gm is in is : (a) 0.1 (b) 0.2 (c) 0.3 (d) 0.4

    		•
  • Q : Explain the preparation of phenols. The

    The methods used for the preparation of phenols are given below:    From aryl sulphonic acids

    		•
  • Q : Describe Thermodynamics Properties The

    The free energy property leads to convenient expressions for the volume and pressure dependence of internal energy, enthalpy and the heat capacities.All the properties of a chemical system, a sample of a substance, or a mixture of substances have some fixe

    		•
  • Q : Question based on relative lowering of

    Give me answer of this question. When a non-volatile solute is dissolved in a solvent, the relative lowering of vapour pressure is equal to: (a) Mole fraction of solute (b) Mole fraction of solvent (c) Concentration of the solute in grams per litre (d) Concentratio

    		•
  • Q : What do you mean by the term dipole

    What do you mean by the term dipole moment? Briefly describe it.

    		•
  • Q : Group Cations Explain how dissolving

    Explain how dissolving the Group IV carbonate precipitate with 6M CH3COOH, followed by the addition of extra acetic acid, establishes a buffer with a pH of approximately

    		•
  • Q : Surface Tension Vapour Pressure The

    The vapor pressure of small liquid drops depends on the drop size. Although the surface properties of a liquid are different from those of the bulk liquid, the special surface properties can be ignored except in a few situations. One is the case in which a liquid is dispersed into fine dr

    		•