How Does Solvent Type Affect the Activity of 2-Pentanone?

[ghelman]

Hey everyone,

I need help with this question:

Homework Statement

2-pentanone is an important industrial intermediate. When using the pure liquid as the reference state, in which solvents (examples and explanations) would you expect it to have an activity of a) less than one, b) one, and c) greater than one?

The Attempt at a Solution

I feel like it must be a pretty simple question if I knew how activity was related to intermolecular forces- but I don't! Can anyone enlighten me on that?

Thanks!

 

[nate808]

Hi there,

Activity is a measure of the effective concentration of a substance in a mixture, compared to its concentration in its pure state. It is related to intermolecular forces because these forces determine how well a substance interacts with its surroundings and therefore how much it contributes to the overall concentration in a mixture.

In the case of 2-pentanone, a) less than one activity would be expected in solvents with strong intermolecular forces, such as water or alcohols. This is because the strong forces between these solvents and 2-pentanone would prevent the 2-pentanone molecules from escaping into the gas phase, resulting in a lower effective concentration in the mixture.

b) An activity of one would be expected in solvents with similar intermolecular forces as 2-pentanone, such as other ketones or ethers. In these solvents, the intermolecular forces are similar enough that the 2-pentanone molecules can easily mix in and contribute to the overall concentration without being significantly hindered by the solvent.

c) Greater than one activity would be expected in solvents with weaker intermolecular forces, such as hydrocarbons or halogenated solvents. These solvents have weaker interactions with 2-pentanone, allowing the 2-pentanone molecules to easily escape into the gas phase and contribute to the overall concentration in the mixture.

I hope this helps! Let me know if you have any further questions or need clarification.