Which from following mixtures exhibits positive deviation from Raoult's law?

Positive deviation from Raoult's law occurs when vapor pressure exceeds predictions due to weaker intermolecular attractions between mixture components than within pure substances.

Ethanol and acetone demonstrate this behavior: ethanol's strong hydrogen bonds are disrupted upon mixing, while acetone provides only dipole-dipole interactions. The resultant ethanol-acetone interactions are weaker than pure ethanol's hydrogen bonding, increasing vapor pressure.

Benzene-toluene mixtures exhibit near-ideal behavior with similar dispersion forces. Chloroform-acetone forms stronger hydrogen bonds ($\text{C-H}\cdots\text{O=C}$) than pure components, showing negative deviation. Phenol-aniline also demonstrates negative deviation through enhanced hydrogen bonding between phenolic hydrogens and aniline nitrogens.

Thus, only ethanol-acetone shows positive deviation.