Why there no change in volume and enthalpy of solution when two components are mixed
What is the definition of an ideal solution?
Solution which follows raoutlts law over all range of concenteration.
And its components are of same nature
An ideal solution is one for which the change in volume and enthalpy upon mixing are zero. Raoults law follows indirectly from this. Many combinations of real species exhibit behavior close to ideal solution behavior.
So my question is why enthalpy or volume doesnt change
If you mix two volumes of the same liquid, the total volume doesn't change, and there are no heat effects because the molecular interactions don't change. If you mix two liquids whose molecules are very similar, the volume and enthalpy will change very little, because the energetic interactions between the molecules of the solution will be very similar to those of the original pure liquids. For more details on this, see Smith and Van Ness, intro to chem engg thermo.
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