Draw the Lewis structure for COCl2, including lone pairs.What is the molecular shape of COCl2? The C – Cl bond in COCl2 is polar o nonpolar? What is the Cl – C – Cl bond angle ?The molecule COCl2 is polar or nonpolar?
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| Topic | Lewis structure and molecular properties of COCl2 |
| What is this question about..? | This question is about the molecular structure and polarity of COCl2. The first part requires the student to draw the Lewis structure of COCl2 and identify any lone pairs. The second part involves identifying the molecular shape and bond angles of the compound, and determining whether it is polar or nonpolar based on the polarity of its bonds |
The correct answer and explanation is:
Answer:
- Lewis Structure of COCl₂:
- Carbon (C) is the central atom.
- Carbon forms a double bond with oxygen (O) and single bonds with two chlorine (Cl) atoms.
- Each Cl atom has three lone pairs, and O has two lone pairs.
- The Lewis structure is:
O
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C — Cl
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Cl
- Molecular Shape of COCl₂:
The molecular shape is trigonal planar due to three regions of electron density (double bond to O and two single bonds to Cl) around the central carbon atom. - C–Cl Bond Polarity:
The C–Cl bond is polar because chlorine is more electronegative than carbon, creating a dipole moment. - Cl–C–Cl Bond Angle:
The Cl–C–Cl bond angle is approximately 120°, consistent with the trigonal planar shape. - Polarity of COCl₂:
The molecule is polar due to the asymmetrical distribution of dipoles. The highly electronegative oxygen pulls electron density towards itself, creating a net dipole moment.
Explanation
The molecule COCl₂ (phosgene) consists of a carbon atom double-bonded to oxygen and single-bonded to two chlorine atoms. To construct the Lewis structure, the total valence electrons (C: 4, O: 6, Cl: 7 each) are distributed to satisfy the octet rule for all atoms. Carbon is the central atom because it forms the most bonds.
COCl₂ adopts a trigonal planar geometry, as predicted by the Valence Shell Electron Pair Repulsion (VSEPR) theory. This shape arises because the carbon atom has three regions of electron density around it, which repel each other to maximize separation. The bond angle between the chlorine atoms is approximately 120°.
The C–Cl bond is polar due to the difference in electronegativity (Cl > C). Similarly, the C=O bond is highly polar because oxygen is significantly more electronegative than carbon. These polar bonds create dipoles, which do not cancel out due to the asymmetry of the molecule.
As a result, COCl₂ is polar. The oxygen atom creates a stronger pull on electron density compared to the two chlorines, leading to a net dipole moment. This property influences the molecule’s reactivity and physical properties, such as its solubility in polar solvents.
Understanding COCl₂’s molecular structure and polarity is essential for predicting its chemical behavior, including interactions with other molecules and its role in industrial processes.