Listed in no particular order, the C-O bond lengths in carbon monoxide, CH2O, and methanol are 0.121 nm, 0.143 nm, and 0.113 nm. Which one has a C-O bond length of 0.143 nm? A) carbon monoxide B) CH2O C) CH3OH
The Correct Answer and Explanation is:
The compound with a C-O bond length of 0.143 nm is B) CH2O (formaldehyde).
Here’s why:
- Carbon Monoxide (CO): The bond length in carbon monoxide (CO) is 0.121 nm. In CO, carbon and oxygen share a triple bond, which is a very strong and short bond. A shorter bond length corresponds to the strength of the bond. Given that CO has a triple bond, this results in a significantly shorter bond length compared to other compounds.
- CH2O (Formaldehyde): In formaldehyde, the carbon-oxygen bond is part of a double bond structure. A double bond is not as short as a triple bond but still stronger than a single bond. The C-O bond length in formaldehyde is 0.143 nm, which falls within the typical range for a C=O (double bond) bond. The bond length in formaldehyde is slightly longer than in carbon monoxide, which is consistent with its lower bond order (double bond vs. triple bond).
- Methanol (CH3OH): In methanol, the C-O bond length is 0.113 nm. Methanol has a single bond between carbon and oxygen, which is the longest among these three compounds. The single bond is weaker and longer than a double or triple bond, which explains the shorter bond length.
Summary:
- Carbon monoxide (CO) has a triple bond (shortest C-O bond).
- Formaldehyde (CH2O) has a double bond (intermediate C-O bond length).
- Methanol (CH3OH) has a single bond (longest C-O bond).
Thus, CH2O (formaldehyde) has the C-O bond length of 0.143 nm.
