What kind of intermolecular forces act between a formaldehyde (H_2CO) molecule and a carbon monoxide molecule?
The Correct Answer and Explanation is:
Correct Answer:
The intermolecular forces that act between a formaldehyde (H₂CO) molecule and a carbon monoxide (CO) molecule are dipole-dipole interactions and London dispersion forces.
Explanation:
To understand the intermolecular forces between formaldehyde and carbon monoxide, we must first look at the molecular structure and polarity of both substances.
Formaldehyde (H₂CO):
Formaldehyde consists of a carbon atom double-bonded to an oxygen atom and single-bonded to two hydrogen atoms. The carbon-oxygen double bond is highly polar because oxygen is much more electronegative than carbon. This makes formaldehyde a polar molecule with a partial negative charge on the oxygen and a partial positive charge near the hydrogen atoms.
Carbon Monoxide (CO):
Carbon monoxide is a small, diatomic molecule with a triple bond between carbon and oxygen. Although it is often mistaken as nonpolar due to its linear structure, CO is slightly polar. Oxygen is more electronegative than carbon, which gives the oxygen atom a partial negative charge and the carbon a partial positive charge.
Types of Intermolecular Forces:
- Dipole-Dipole Interactions:
Both H₂CO and CO are polar molecules. Dipole-dipole forces arise from the electrostatic attraction between the partially positive region of one molecule and the partially negative region of another. In this case, the slightly negative oxygen in CO can attract the slightly positive hydrogen in formaldehyde, and vice versa. These interactions are stronger than dispersion forces and are a major contributor to the attraction between these molecules. - London Dispersion Forces:
These are weak, temporary attractions caused by momentary changes in electron distribution. All molecules experience dispersion forces, regardless of polarity. They are especially important for nonpolar molecules but are present between polar ones as well.
In summary, the interaction between H₂CO and CO involves dipole-dipole forces due to their polarity and London dispersion forces due to temporary dipoles. Hydrogen bonding does not occur because CO lacks hydrogen atoms bonded to highly electronegative atoms like nitrogen, oxygen, or fluorine.
