Question

If you mixed two liquids, will their apparent volume be different than the total volume of unmixed pure components? Why?

Answer 1

When we mix two liquids , there is no change in volume than the total voluem of pure components only when the liquids form an ideal solution (delta V =0)

But most of the cases , the two liquids do not form idesl solution, then delta V is not equal to zero, that is the net volume may be less than or greater than the sum of volumes of two liquids.

This happens becuse of the difference in attractive forces between the two liquids.

If the secondary attractive forces between the two liquid molecules are less than the individual liquid moelcules , then volume of mixture is greater than the sum of individual volumes [solute -solvent interactions weaker than solute-solute and solvent-solvent interactions].Eg water -sulfuric acid system

If the attractive forces between the two liquids are stronger than the individual liquids , then the volume of mixture is less than the sum of individual volumes [solute -solvent interactions stronger than solute-solute and solvent-solvent molecules] eg. chlorofm -acetone system