increasing order of boiling points of NO2, KCl and N2
Wouldn't you think N2 < NO2 < KCl?
To determine the increasing order of boiling points for NO2, KCl, and N2, you need to consider the intermolecular forces present in each compound.
Boiling points depend on the strength of the forces holding the molecules together. The stronger the intermolecular forces, the higher the boiling point.
Let's examine each compound and analyze the intermolecular forces:
1. NO2 (Nitrogen dioxide): NO2 consists of two oxygen atoms bound to a nitrogen atom. It forms temporary dipole-dipole forces due to the polarity of the molecule. These forces arise due to the attraction between the positive end of one molecule and the negative end of another. While NO2 has dipole-dipole forces, it also exhibits weak London dispersion forces.
2. KCl (Potassium chloride): KCl is an ionic compound composed of potassium (K+) and chloride (Cl-) ions. Ionic compounds have strong electrostatic forces of attraction between the positive and negative ions. These forces are called ionic bonds and are significantly stronger than dipole-dipole or London dispersion forces.
3. N2 (Nitrogen gas): N2 is a diatomic molecule consisting of two nitrogen atoms. It is nonpolar, meaning it does not have a permanent dipole moment. Therefore, N2 exhibits only weak London dispersion forces.
Based on this analysis, we can conclude that the increasing order of boiling points is as follows:
N2 < NO2 < KCl
Nitrogen gas (N2) has the lowest boiling point as it only exhibits weak London dispersion forces. Nitrogen dioxide (NO2) has a higher boiling point due to the additional dipole-dipole forces. Potassium chloride (KCl) has the highest boiling point because it forms strong ionic bonds.
Remember, this analysis is based on the assumption that we are comparing the boiling points under similar conditions, such as pressure.