Yes, there was a difference in my results between the solubilities of benzophenone in methyl alcohol and benzophenone in hexane. Benzophenone [essentially nonpolar (slightly polar due to the C=O bond)] was soluble in methyl alcohol, but only partially soluble in hexane. The reason for this is that methyl alcohol has an intermediate polarity, whereas hexane is nonpolar. FINISH. At this point I got confused... if benzophenone is basically nonpolar and hexane is nonpolar, then why wasn't benzophenone fully soluble in hexane and why was it fully soluble in methyl alcohol, rather than only partially?
I understand your confusion, and it's a good question. Although both benzophenone and hexane are nonpolar, there are other factors that can affect solubility.
Solubility is determined by the interactions between the solute (benzophenone) and the solvent (methyl alcohol or hexane). In the case of benzophenone, it has a slightly polar C=O bond, which means it has some polarity, albeit very weak. Polar solvents like methyl alcohol have molecules with permanent dipoles. These dipoles can interact with the polar C=O bond in benzophenone, allowing it to dissolve well in methyl alcohol.
On the other hand, hexane is a nonpolar solvent with no permanent dipoles. While benzophenone is also nonpolar, the weak polarity of its C=O bond can still interact with the nonpolar hexane molecules. However, because the interaction strength between the nonpolar benzophenone and nonpolar hexane is weaker than the interaction between polar benzophenone and polar methyl alcohol, the solubility of benzophenone in hexane is only partial.
To summarize, even though both benzophenone and hexane are nonpolar, the presence of the slightly polar C=O bond in benzophenone allows it to dissolve better in the polar solvent methyl alcohol compared to the nonpolar solvent hexane. It's the nature of the interactions between the solute and the solvent that ultimately determine solubility.
The solubility of a compound in a particular solvent is determined by the intermolecular interactions between the compound and the solvent molecules. In the case of benzophenone, which is essentially nonpolar, its solubility in a solvent depends on the strength of the intermolecular forces between benzophenone and the solvent molecules.
Firstly, let's consider the solubility of benzophenone in hexane. Hexane is a nonpolar solvent, meaning it consists of molecules that have relatively equal distribution of charge (or lack thereof) throughout the molecule. In this case, the only significant intermolecular forces at play are London dispersion forces, which are relatively weak forces caused by temporary fluctuations of electron density. Benzophenone, being nonpolar itself, also experiences London dispersion forces.
Although both benzophenone and hexane are nonpolar, there can still be differences in the strength of their respective London dispersion forces. It is possible that other factors, such as molecular shape or size, could affect the strength of these forces. These differences in intermolecular forces between benzophenone and hexane can account for the partial solubility of benzophenone in hexane. While some of the benzophenone molecules may be able to interact enough with the hexane molecules to be dissolved, not all of them can overcome the relatively weak intermolecular forces and become fully soluble.
On the other hand, methyl alcohol (methanol) is a polar solvent. It contains a polar hydroxyl functional group (-OH) that makes it capable of forming strong hydrogen bonds with other polar molecules. Benzophenone, although nonpolar, still possesses a polar C=O (carbonyl) group. This polar group allows benzophenone to form hydrogen bonds with the polar hydroxyl groups of methyl alcohol. This interaction between the polar carbonyl group of benzophenone and the polar hydroxyl group of methyl alcohol leads to greater solubility of benzophenone in methyl alcohol compared to hexane.
In summary, although benzophenone is essentially nonpolar, it is partially soluble in hexane because of the relatively weak intermolecular forces between benzophenone and hexane molecules. The full solubility of benzophenone in methyl alcohol can be attributed to the stronger intermolecular interactions, specifically hydrogen bonding, between the polar carbonyl group of benzophenone and the polar hydroxyl groups of methyl alcohol.