Which liquid has the highest vapor pressure at 75°c?
(1) ethanoic acid (3) propanone
(2) ethanol (4) water

1)  Ethanol

Explanation:

If we will have interactions we will need more energy to break them in order to go from liquid to gas. If we need more energy, therefore, the temperature will be higher.

In this case, we can discard the propanone because this molecule don't have the ability to form hydrogen bonds. (Let's remember that to have hydrogen bonds we need to have a hydrogen bond to a heteroatom, O, N, P or S).

Then we have to analyze the hydrogen bonds formed in the other molecules. For ethanol, we will have only 1 hydrogen bond. For water and ethanoic acid, we will have 2 hydrogen bonds, therefore, we can discard the ethanol.  

For ethanoic acid, we have 2 intramolecular hydrogen bonds. For water we have 2 intermolecular hydrogen bonds, therefore, the strongest interaction will be in the ethanoic acid.

The closer boiling point to the 75ºC is the ethanol (boiling point of 78.8 ºC) therefore these molecules would have enough energy to break the hydrogen bonds and to past from liquid to gas.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

може ли да зареждате повече информация, моля