Consider the resonance structures of formate.
Select the true statements about the resonance structures.
Each carbon-oxygen bond is somewhere between a single and double bond.
Each oxygen atom has a double bond 50% of the time.
The actual structure of formate is an average of the two resonance forms.
The actual structure of formate switches back and forth between the two resonance forms.
The Correct Answer and Explanation is :
Based on the resonance structures of formate, let’s review the statements:
- Each carbon-oxygen bond is somewhere between a single and double bond.
- True. In formate, there are two resonance structures where one oxygen has a double bond to the carbon and the other has a single bond with a negative charge. In reality, the carbon-oxygen bonds are in between a single and double bond because of the delocalization of electrons between the two oxygen atoms. This means that the bond order of each carbon-oxygen bond is not exactly 1 (single bond) or 2 (double bond), but rather an intermediate value.
- Each oxygen atom has a double bond 50% of the time.
- False. The electrons in the resonance structure are delocalized, meaning that the double bond shifts between the two oxygen atoms. Therefore, each oxygen atom has a double bond to the carbon for only part of the time, but it is not necessarily 50% of the time. The average bond order is shared equally between the two oxygens.
- The actual structure of formate is an average of the two resonance forms.
- True. The real structure of formate is a hybrid, or an average, of the two resonance structures. This means that the molecule is not in either one of the two forms at any given time but is rather a blend of both, with electron density shared between the two oxygen atoms.
- The actual structure of formate switches back and forth between the two resonance forms.
- False. The molecule does not “switch” back and forth between the two resonance forms. Instead, the resonance forms represent the same molecule, and the electron density is delocalized. There is no oscillation between them; instead, the molecule exists in a stable, hybridized form.
Explanation:
In formate, the negative charge on the oxygen is delocalized, meaning the electrons are spread out over both oxygen atoms. The two resonance structures show different placements of the double bond, but both contribute to the overall electron distribution. This creates an intermediate bond order between single and double bonds for each carbon-oxygen bond. The molecule does not alternate between the resonance forms, but rather exists in a hybrid state that represents an average of both.
Let me generate the image of the resonance structure for you!
Here is the diagram illustrating the resonance structures of formate. The image shows the two oxygen atoms connected to the central carbon atom with delocalized electron density. This represents the bond order between single and double bonds for the carbon-oxygen bonds. Let me know if you need further clarification!
