'Describe the difference in intermolecular forces between 2-methyl-3-hexanone and 5-methyl-3-hexanol and how this affects the properties of the substances.'
I'm looking at the molecles on Chemspider, and I want to say that because 5-methyl-3-hexanol has a hydroxyl group, it will form hydrogen bonds, whereas 2-methyl-3-hexanone wouldn't. That in turn means 5-methyl-3-hexanol has higher melting and boiling points. Does that sound reasonable, or am I missing something?
Thanks!
reasonable, hydrogen bonding.
Quick clarification question - carbonyl groupts don't form hydrogen bonds, right? Since they don't have hydrogen attached to them, even though there's oxygen, they wouldn't participate in hydrogen bonding?
Both aldehydes and ketones are polar molecules because of the presence of the carbon-oxygen double bond. ... Although the aldehydes and ketones are highly polar molecules, they don't have any hydrogen atoms attached directly to the oxygen, and so they can't hydrogen bond with each other.
Your reasoning is correct. The presence of a hydroxyl group (-OH) in 5-methyl-3-hexanol allows for the formation of hydrogen bonds between molecules. Hydrogen bonding is a strong intermolecular force that occurs when a hydrogen atom is bonded to a highly electronegative atom (such as oxygen, nitrogen, or fluorine) and is attracted to another electronegative atom nearby.
On the other hand, 2-methyl-3-hexanone does not have a hydroxyl group, so it cannot form hydrogen bonds. Instead, it can only experience London dispersion forces, which are relatively weak intermolecular forces that occur due to temporary fluctuations in electron distribution and induce temporary dipoles in neighboring molecules.
As a result, the hydrogen bonding in 5-methyl-3-hexanol is stronger than the London dispersion forces in 2-methyl-3-hexanone. This difference in intermolecular forces affects several properties of the substances, including their melting and boiling points.
Since hydrogen bonds are stronger than London dispersion forces, substances that can form hydrogen bonds generally have higher melting and boiling points compared to substances that only experience London dispersion forces. In this case, 5-methyl-3-hexanol with hydrogen bonding will indeed have higher melting and boiling points compared to 2-methyl-3-hexanone.
Therefore, your reasoning is valid, and you have accurately described the difference in intermolecular forces between 2-methyl-3-hexanone and 5-methyl-3-hexanol, as well as how these forces affect the properties of the substances.