Question

Methanol and acetone can have dipole dipole interaction and hydrogen bonds also ,why they form position deviation

Answer 1

Dear student,
Methanol molecules form dipole-dipole interactions between the partially positive hydrogen and the partially negative oxygen. This bond is also called a hydrogen bond. In pure methanol, molecules are hydrogen-bonded. On adding acetone, its molecules get in between the host molecules and break some of the hydrogen bonds between them. Therefore, the intermolecular attractive forces between the solute-solvent molecules are weaker than those between the solute-solute and solvent-solvent molecules. Due to the weakening of interactions, the solution shows a positive deviation from Raoult's law.
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