differences in solubilities of the different alcohos and phenols with water and with pentane?

Answer 1

A popular aphorism used for predicting solubility is "Like dissolves like"[6] This indicates that a solute will dissolve best in a solvent that has a similar polarity to itself. This is a rather simplistic view, since it ignores many solvent-solute interactions, but it is a useful rule-of-thumb. For example, a very polar (hydrophilic) solute such as urea is highly soluble in highly polar water, less soluble in fairly polar methanol, and practically insoluble in non-polar solvents such as benzene or pentane. In contrast, a non-polar or lipophilic solute such as naphthalene is insoluble in water, fairly soluble in methanol, and highly soluble in non-polar benzene or pentane.
The principle outlined above, that like dissolves like, is the usual guide to solubility with organic systems. For example, petroleum jelly will dissolve in gasoline; both of which are lipophilic. This is because vaseline jelly consists of long carbon chains, as does the gasoline. It will not, on the other hand, dissolve in water, since the polarity of water is too high. Sugar will not dissolve in gasoline, since sugar is too polar in comparison with gasoline. A mixture of gasoline and sugar can therefore be separated by filtration, or extraction with water.
Now, the different alcohols and phenols concerning solubility is with respect to its carbon chain or chains. A very short or no carbon chain makes the molecule polar, thus enable a high solubility in water but not in pentane. A long or several long carbon chain/s make the molecule less polar, or very little polar, enabling a high solubility in pentane but not in water.