If benzophenone is nonpolar, how come it is only partially soluble in hexane (nonpolar)? Also, can H bonding occur?
Can H bonding occur between benzophenone and methyl alcohol? malonic acid and methyl alcohol? biphenyl and methyl alcohol? Please explain.
Benzophenone does have a slight polarity due to the C=O bond but it is not highly polar. You would not expect H bonding to occur BETWEEN molecules of benzophenone. I would think it could occur between benzophenone and methyl alcohol as well as between malonic acid and methyl alcohol. Not between biphenyl and methyl alcohol.
To understand why benzophenone is only partially soluble in hexane, we need to consider the concept of solubility and the intermolecular forces involved.
Solubility depends on the balance between the energy required to break the intermolecular forces and the energy released when new intermolecular forces are formed between the solute and solvent. In the case of benzophenone, it is nonpolar due to the presence of aromatic rings and carbonyl groups, which have similar electronegativities. Its nonpolar nature makes it more likely to dissolve in nonpolar solvents like hexane.
However, while benzophenone is nonpolar overall, it does have polarizable areas within its structure, such as the carbonyl group. These areas can experience induced dipole-induced dipole interactions (also known as London dispersion forces) with the surrounding hexane molecules. This weak intermolecular force contributes to the partial solubility of benzophenone in hexane. Keep in mind that partial solubility means that not all benzophenone molecules will dissolve in hexane, but only a fraction of them.
Moving on to the second part of your question, hydrogen bonding (H-bonding) occurs when a hydrogen atom is bonded to highly electronegative elements like oxygen, nitrogen, or fluorine. H-bonding plays a crucial role in determining the physical properties and solubilities of compounds.
Regarding the potential for H-bonding between benzophenone and methyl alcohol, malonic acid and methyl alcohol, and biphenyl and methyl alcohol, let's examine each case:
1. Benzophenone and methyl alcohol: Benzophenone does not have any hydrogen atoms bonded to highly electronegative elements, so it cannot form H-bonds with methyl alcohol, which does have a hydrogen atom bonded to oxygen. Therefore, H-bonding cannot occur between benzophenone and methyl alcohol.
2. Malonic acid and methyl alcohol: Malonic acid has two carboxylic acid groups (-COOH), each of which contains a hydrogen atom bonded to oxygen. Methyl alcohol, as mentioned earlier, also has a hydrogen atom bonded to oxygen. This allows for the possibility of H-bonding between malonic acid and methyl alcohol. H-bonds can form between the hydrogen atoms of malonic acid and the oxygen atom of methyl alcohol.
3. Biphenyl and methyl alcohol: Biphenyl, similar to benzophenone, is nonpolar due to the presence of aromatic rings. It does not have any hydrogen atoms bonded to highly electronegative elements, so H-bonding cannot occur between biphenyl and methyl alcohol.
In summary, while benzophenone is nonpolar, it can still exhibit partial solubility in hexane due to the presence of polarizable areas in its structure. H-bonding can occur between malonic acid and methyl alcohol but not between benzophenone and methyl alcohol or biphenyl and methyl alcohol due to the absence of suitable hydrogen atoms bonded to highly electronegative elements.