The liquid that has the lowest vapor pressure at 65.0 °C is ethanoic acid.
As shown in the attached image, the figure in the image shows the relation of vapor pressure with temperature for the mentioned four liquids (ethanoic acid, propanone
, ethanol and water).
Extend a verical line at 65.0 °C and then get the corresponding vapor pressures of the four liquids.
You will find that the liquid that has the lowest vapor pressure at 65.0 °C is ethanoic acid.
