Why do carboxylic acids generally have higher melting and boiling points than alcohols, ketones, and aldehydes of comparable mass?
The carboxylic acids are quite polar and they form hydrogen bonding just as alcohols, ketones and aldehydes do; HOWEVER, a pair of acids is held together by TWO hydrogen bonds instead of the one formed by alcohols, ketones, and aldehydes.
I've tried to draw a structure to chow you on this board and can't do it. But the OH of one COOH is hydrogen bonded to an O on the COOH of another molecule and the other molecule in turn bonds its OH with the O on the first molecule. So we have quasi dimers.
becos it does, duh. where is your brain. think about it. it undergoes hydrogen bonding, meaning that the bonds are so strong. ur so dumb. just chill bruh and stop havin a heart attack over some lousy chem question. you'll be fine. jeez.
Carboxylic acids generally have higher melting and boiling points than alcohols, ketones, and aldehydes of comparable mass due to several key factors:
1. Intermolecular hydrogen bonding: Carboxylic acids have a carboxyl functional group (-COOH), which allows for the formation of strong intermolecular hydrogen bonds. The presence of hydrogen bonding leads to stronger attractive forces between molecules, requiring more thermal energy to break these bonds and increase the melting and boiling points.
2. Size and shape: Carboxylic acids are typically larger and more elongated molecules compared to alcohols, ketones, and aldehydes of similar mass. The larger size and elongated shape allow for greater surface contact area between molecules, leading to stronger intermolecular forces and higher melting and boiling points.
3. Polarity: Carboxylic acids are highly polar due to the presence of the carbonyl group (C=O) and the hydroxyl group (-OH). The polar nature of carboxylic acids facilitates stronger dipole-dipole interactions between molecules, contributing to higher melting and boiling points.
Overall, the combination of intermolecular hydrogen bonding, size and shape, and polarity in carboxylic acids results in stronger intermolecular forces and higher melting and boiling points compared to alcohols, ketones, and aldehydes of similar mass.
Carboxylic acids generally have higher melting and boiling points than alcohols, ketones, and aldehydes of comparable mass due to the presence of strong intermolecular hydrogen bonding. To understand this, let's first explore the concept of intermolecular forces.
Intermolecular forces are the attractive forces between molecules. They determine the physical properties of a substance, such as melting point, boiling point, and solubility. There are several types of intermolecular forces, including London dispersion forces, dipole-dipole interactions, and hydrogen bonding.
In the case of carboxylic acids, the presence of a carboxyl group (-COOH) allows for the formation of hydrogen bonds. Hydrogen bonds are a special type of dipole-dipole interaction that occurs when a hydrogen atom is bonded to a highly electronegative atom (such as oxygen or nitrogen) and forms an attractive force with a lone pair of electrons on another electronegative atom.
Carboxylic acids contain both a carbonyl group (C=O) and a hydroxyl group (OH). The oxygen atoms in these groups can participate in hydrogen bonding. For example, in acetic acid (CH3COOH), the oxygen in the hydroxyl group can form hydrogen bonds with other acetic acid molecules.
In contrast, alcohols, ketones, and aldehydes lack this specific combination of functional groups that can form extensive hydrogen bonding networks, or they have weaker hydrogen bonding abilities. Alcohols have a hydroxyl group but usually lack a carbonyl group, while ketones and aldehydes have a carbonyl group but lack a hydroxyl group. As a result, the hydrogen bonding in these compounds is typically weaker than in carboxylic acids.
The presence of strong intermolecular hydrogen bonding in carboxylic acids leads to increased attraction between molecules, requiring more energy to break these interactions, resulting in higher melting and boiling points compared to other compounds of similar mass.
In summary, carboxylic acids generally have higher melting and boiling points than alcohols, ketones, and aldehydes of comparable mass due to the presence of strong intermolecular hydrogen bonding resulting from the combination of a carbonyl and hydroxyl functional group.