Solubility doubt

jaumzaum

I was solving an exercise where I had to judge (true or false) 5 statements. One of them said:

"Sodium benzoate is more soluble in water than in toluene"

The book answer is true, but I don't know how to compare it.

I mean, sodium benzoate is ionic, and water is very polar, so the solubility of the salt in water should be great. Nevertheless sodium benzoate has a aromatic nucleus, that is the same of toluene, so they should share pretty much the same molecular interactions and one should reasonably dissolve another too. Am I thinking wrong? If not, how should I compare both of the solubilities?

Thanks
John

chill_factor

Nope you're thinking too hard. If it is ionic in general it is soluble in polar solvents.

Now there is a cutoff. A 500000 dalton hydrocarbon polymer with a single charged group is obviously not going to be soluble. Where is the cutoff? Hard to say.

That requires computational chemistry.