Draw lewis structures of H2CO2 also draw the correct symbols to show the polar covalent bonds within these molecules
The Correct Answer and Explanation is:
Lewis Structure of H₂CO₂ (Formic Acid)
Molecular Formula: H₂CO₂
IUPAC Name: Methanoic acid (commonly known as formic acid)
Structure:
Formic acid contains:
- Two hydrogen atoms (H)
- One carbon atom (C)
- Two oxygen atoms (O)
It has the following correct Lewis structure:
O
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H–C–O–H
Or, drawn with lone pairs and polar bond symbols:
δ− δ+
O:: ═ C – O: – H
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H (lone pairs)
Explanation:
- The carbon (C) atom forms four bonds: one double bond with an oxygen (C=O), one single bond with another oxygen (C–O), and one single bond with a hydrogen (C–H).
- The OH group (O–H) represents a hydroxyl group.
- Oxygen atoms have lone pairs (each has 2 lone pairs in this structure).
- The C=O and C–O bonds are polar covalent because oxygen is significantly more electronegative than carbon. Similarly, the O–H bond is also polar covalent.
Explanation of Lewis Structure and Polarity
The Lewis structure of H₂CO₂ (formic acid) reveals how the atoms are bonded and where electrons are located. Carbon is the central atom because it can form four bonds. One oxygen forms a double bond (C=O), and the other forms a single bond with both the carbon and a hydrogen atom (C–O–H). The remaining hydrogen is bonded directly to the carbon (C–H).
Each bond is made of shared electron pairs, with oxygen atoms also having unshared (lone) pairs. In total, each oxygen atom needs 8 valence electrons (including bonding and lone pairs) to satisfy the octet rule. Carbon also reaches 8 electrons through its four bonds.
This structure ensures that all atoms follow the octet (or duet for hydrogen) rule, making it a stable configuration.
The polarity of bonds arises due to the difference in electronegativity:
- Oxygen is more electronegative than both carbon and hydrogen.
- Thus, the C=O, C–O, and O–H bonds are polar covalent.
- The dipole moment points toward the oxygen atom in each of these bonds (from δ+ to δ−).
- These polar covalent bonds contribute to the overall polarity of the molecule, making formic acid a polar molecule.
The polar nature of H₂CO₂ gives it properties like high solubility in water and the ability to participate in hydrogen bonding—important characteristics in biological and chemical systems.
