---
title: "The Lewis diagram for formic acid, \\(\\text{HCOOH}\\), and two resonance contributors for the formate ion, \\(\\text{HCOO}^-\\), are shown above. Based on these representations, which of the following correctly compares the carbon-oxygen bonds in the two species?"
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url: "https://nerd-notes.com/ubq/123521/"
date_modified: "2026-09-28T12:00:01+00:00"
---

# The Lewis diagram for formic acid, \(\text{HCOOH}\), and two resonance contributors for the formate ion, \(\text{HCOO}^-\), are shown above. Based on these representations, which of the following correctly compares the carbon-oxygen bonds in the two species?

The Lewis diagram for formic acid, \(\text{HCOOH}\), and two resonance contributors for the formate ion, \(\text{HCOO}^-\), are shown above. Based on these representations, which of the following correctly compares the carbon-oxygen bonds in the two species?

![A grayscale diagram displays two framed structural panels side by side. The left panel is labeled \(\text{HCOOH}\) and shows a single Lewis structure: a central \(\text{C}\) atom with a single bond to a left-side \(\text{H}\) atom, a double bond to an upper-right \(\text{O}\) atom carrying exactly 2 lone pairs, and a single bond to a lower-right \(\text{O}\) atom carrying exactly 2 lone pairs, which in turn is single-bonded to a terminal \(\text{H}\) atom. No lone pairs exist on the \(\text{C}\) atom or \(\text{H}\) atoms. The right panel is labeled \(\text{HCOO}^-\) and shows two structures enclosed in large brackets with a superscript minus sign: Structure 1 has a central \(\text{C}\) single-bonded to a left-side \(\text{H}\), double-bonded to an upper-right \(\text{O}\) with 2 lone pairs, and single-bonded to a lower-right \(\text{O}\) with 3 lone pairs. A double-headed horizontal resonance arrow points to Structure 2, which has a central \(\text{C}\) single-bonded to a left-side \(\text{H}\), single-bonded to an upper-right \(\text{O}\) with 3 lone pairs, and double-bonded to a lower-right \(\text{O}\) with 2 lone pairs. No other particles, labels, text, or annotations appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1790596801-fPwdlL.jpg)

- **A.** The carbon-oxygen bonds in \(\text{HCOO}^-\) have a bond order of \(1\), making both bonds equal in length to the \(\text{C}-\text{O}\) single bond in \(\text{HCOOH}\).
- **B.** The two carbon-oxygen bonds in \(\text{HCOO}^-\) are equivalent with a bond order of \(1.5\), making their bond length intermediate between the \(\text{C}-\text{O}\) single bond and the \(\text{C}=\text{O}\) double bond in \(\text{HCOOH}\).
- **C.** The formate ion rapidly oscillates between the two resonance structures, so at any single instant one \(\text{C}-\text{O}\) bond is shorter than the other.
- **D.** The two carbon-oxygen bonds in \(\text{HCOO}^-\) each have a bond order of \(2\) due to delocalization, making both bonds shorter and stronger than the \(\text{C}=\text{O}\) double bond in \(\text{HCOOH}\).

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