CHE 101 Chapter Notes - Chapter 13: Benzene, Gas Constant, Semipermeable Membrane
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Revision Notes on Solution:
A solution is a homogeneous mixture of two (or more) substances, the composition of which may
vary between certain limits. A solution consisting of two components is called binary solution
component which is present in large quantity is called solvent
and the component which is small in
quantity is called solute
. If both components are in same physical state.
Type of Solutions
All the three states of matter (gas, liquid or solid) may behave either
as solvent or solute. Depending on the state of solute or solvent, mainly there may be the following
seven types of binary solutions.
Aerated water (CO2 + H2O)
Hydrogen in palladium
Alcohol in water, benzene in toluene
Mercury in zinc amalgam
●The pressure exerted by vapours over the liquid surface at equilibrium is called vapour
of the liquid.
●If solute is non volatile solid or liquid the vapour pressure of solution is equal to partial
vapour pressure of solvent in the solution.
●If the solute is volatile solid or liquid, then vapour pressure will be equal to the sum of
partial vapour pressure of solute and that of solvent.
“The partial vapour pressure of any component in the solution is directly proportional to its
CO2 dissolved in water
Sugar in water, common salt in water
For a binary solution of two components A and B,
PA = XA
PB = XB
P0A = vapour pressure of component A in pure state.
PA = vapour pressure of component A in the solution.
P0B = vapour pressure of component B in pure state.
PB = vapour pressure of component B in the solution
Limitations of Raoult’s Law
●Raoult’s law is applicable only to very dilute solutions.
●It is applicable to solutions containing non-volatile solute only.
●It is not applicable to solutes which dissociate or associate in a particular solution
Raoult’s Law in Combination with Dalton’s Law of Partial Pressure:
PT = X
A P0A + X
B P0B = P0B + (P0A -P0B) X
PT = Total Vapour Pressure of the Solution.
Ideal and Non-Ideal Solutions: