Ideal and Non-Ideal solution

Ideal and Non-Ideal solution

Table: Ideal and non-ideal solutions

Ideal solutionsNon-ideal solutions
Positive deviation from Raoult's lawNegative deviation from Raoult's law
1. Obey Raoult's law at every range of concentration.1. Do not obey Raoult's law.1. Do not obey Raoult's law.
2. neither heat is evolved nor absorbed during dissolution. 2. Endothermic dissolution; heat is absorbed. 2. Exothermic dissolution; heat is evolved.
3. total volume of solution is equal to sum of volumes of the components.3. Volume is increased after dissolution.3. Volume is decreased during dissolution.

4. i.e.,



5. interactions should be same, i.e., 'A' and 'B' are identical in shape, size and character.5. attractive force should be weaker than and attractive forces. 'A' and 'B' have different shape, size and character. 5. attractive force should be greater than and attractive forces. 'A' and 'B' have different shape, size and character.
6. Escaping tendency of 'A' and 'B' should be same in pure liquids and in the solution.6. 'A' and 'B' escape easily showing higher vapour pressure than the expected value.6. Escaping tendency of both components 'A' and 'B' is lowered showing lower vapour pressure than expected ideally.


Dilute solutions;

benzene + toluene:

n-hexane + n-heptane;

chlorobenzene + bromobenzene;

ethyl bromide + ethyl iodide;

n-butyl chloride + n-butyl bromide


Acetone +ethanol

acetone +:

water + methanol;

water + ethanol;



acetone + benzene;


cyclohexane + ethanol


Acetone + aniline;

acetone + chloroform;


chloroform + diethyl ether;

water + HCl;

acetic acid + pyridine;

chloroform + benzene


Graphical representation of ideal and non-ideal solutions

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