Arrange the following compounds in order of increasing boiling point.
butanal
1-butanol
diethylamine
tartaric acid
butane
butanoic acid
and can you please explain why?
Use molar mass and H bonding to determine. The higher molar mass (more van der Walls forces) the higher the b.p.
The more H bonding (polarity) the higher the b.p.
Butane, for example, would be the lowest b.p. You can look these up on google and see if you have them right.
To arrange the compounds in order of increasing boiling point, we need to consider their respective intermolecular forces. The stronger the intermolecular forces, the higher the boiling point of a compound.
Here is the list of the compounds arranged in order of increasing boiling point:
1. Butane: Butane consists only of London dispersion forces, which are the weakest intermolecular forces. Therefore, it has the lowest boiling point.
2. Butanal: Butanal has stronger intermolecular forces compared to butane. It possesses London dispersion forces, as well as dipole-dipole interactions. These additional dipole-dipole interactions result from the partial positive charge on the carbon atom and the partial negative charge on the oxygen atom of the aldehyde group. Hence, it has a higher boiling point compared to butane.
3. Diethylamine: Diethylamine, an amine, can participate in hydrogen bonding due to the presence of the nitrogen atom. Hydrogen bonding is a stronger intermolecular force than London dispersion forces or dipole-dipole interactions. Therefore, diethylamine has a higher boiling point than butanal.
4. Butanoic acid: Butanoic acid contains a carboxyl group, which makes it capable of forming multiple hydrogen bonds. The presence of these stronger hydrogen bonds gives butanoic acid a higher boiling point than diethylamine.
5. Tartaric acid: Tartaric acid, like butanoic acid, contains carboxyl groups capable of forming hydrogen bonds. However, tartaric acid has two carboxyl groups, which allows for a more extensive hydrogen bonding network. As a result, tartaric acid has a higher boiling point than butanoic acid.
6. 1-Butanol: 1-Butanol has the highest boiling point in this list. It has hydrogen bonding like diethylamine, but the presence of a longer hydrocarbon chain enhances the intermolecular forces. The longer chain increases the surface area available for intermolecular interactions, resulting in stronger dispersion forces. Consequently, 1-butanol has the highest boiling point among the given compounds.
To determine the order of increasing boiling point, we need to consider the intermolecular forces present in each compound. These forces include London dispersion forces, dipole-dipole interactions, and hydrogen bonding.
First, let's analyze each compound individually:
1. Butanal: Butanal is an aldehyde, and it exhibits London dispersion forces and dipole-dipole interactions. However, it does not have a hydrogen atom bonded to an oxygen or nitrogen atom, so it does not have hydrogen bonding.
2. 1-Butanol: 1-Butanol is an alcohol, and it exhibits London dispersion forces, dipole-dipole interactions, and hydrogen bonding. The hydrogen bonding in 1-butanol is stronger than in butanal because it has a hydrogen atom bonded to an oxygen atom.
3. Diethylamine: Diethylamine is an amine, and it exhibits London dispersion forces and dipole-dipole interactions. It also has a hydrogen atom bonded to a nitrogen atom, allowing for hydrogen bonding. However, the hydrogen bonding in diethylamine is not as strong as in 1-butanol because nitrogen is less electronegative than oxygen.
4. Tartaric acid: Tartaric acid contains carboxylic acid groups (-COOH), which can form strong hydrogen bonds. In addition to London dispersion forces and dipole-dipole interactions, it has two hydrogen atoms bonded to oxygen atoms, enabling it to have stronger hydrogen bonding than diethylamine or 1-butanol.
5. Butane: Butane is an alkane and exhibits only London dispersion forces. It lacks functional groups that would allow for stronger intermolecular forces like dipole-dipole interactions or hydrogen bonding.
6. Butanoic acid: Butanoic acid is a carboxylic acid, similar to tartaric acid. It exhibits London dispersion forces, dipole-dipole interactions, and strong hydrogen bonding due to the presence of two hydrogen atoms bonded to oxygen atoms.
Based on this analysis, we can rank the compounds in order of increasing boiling point:
butane < butanal < diethylamine < 1-butanol < butanoic acid < tartaric acid
In general, as the strength of intermolecular forces (such as hydrogen bonding) increases, the boiling point of a compound also increases.