# A sample of ethanoic acid is at 85°C. At a pressure of 50 kPa, what increase in temperature is needed to reach the boiling point of ethanoic acid?

The normal boiling point of ethanoic acid is $118 - 119$ ""^@C. This is a physical property of acetic acid, which you probably would not know offhand. So at $118 - 119$ ""^@C, the vapour pressure of acetic acid is $1$ $a t m$.
At $50$ $k P a$, a reduced pressure, the boiling point of acetic acid is unknown, and is the subject of experiment, which we ain't got. Of course it would be less than $118 - 119$ ""^@C, but we need more data.