Predict the molecular geometry of each interior atom in acetic acid CH3COOH. Drag the appropriate labels to their respective targets. linear trigonal planar bent tetrahedral Atom Carbon (left) Number of Electron Groups 4 3 Number of Lone Pairs 0 0 2 Molecular Geometry Carbon (right) Oxygen
The Correct Answer and Explanation is :
To determine the molecular geometry of each interior atom in acetic acid (CH₃COOH), we examine the structure and consider the number of electron groups and lone pairs around each atom.
1. Carbon (left) – CH₃ group
- Number of Electron Groups: 4 (three single bonds to hydrogen and one single bond to the adjacent carbon).
- Number of Lone Pairs: 0.
- Molecular Geometry: Tetrahedral. This carbon atom is sp³ hybridized, with its bonds arranged in a tetrahedral geometry to minimize electron repulsion.
2. Carbon (right) – COOH group
- Number of Electron Groups: 3 (one double bond to oxygen, one single bond to the other oxygen, and one single bond to the adjacent carbon).
- Number of Lone Pairs: 0.
- Molecular Geometry: Trigonal planar. This carbon atom is sp² hybridized. The three groups are arranged in a planar triangular shape, ensuring minimal electron pair repulsion.
3. Oxygen (in C=O double bond)
- Number of Electron Groups: 3 (one double bond to carbon and two lone pairs).
- Number of Lone Pairs: 2.
- Molecular Geometry: Trigonal planar. The oxygen atom is sp² hybridized. Its lone pairs and the bonding electrons create a planar arrangement.
4. Oxygen (in OH group)
- Number of Electron Groups: 4 (one single bond to carbon and two lone pairs).
- Number of Lone Pairs: 2.
- Molecular Geometry: Bent. The oxygen atom is sp³ hybridized. The two lone pairs force the molecular geometry into a bent shape.
Summary
- Carbon (left): Tetrahedral.
- Carbon (right): Trigonal planar.
- Oxygen (C=O): Trigonal planar.
- Oxygen (OH): Bent.
Explanation
The molecular geometry is determined by the VSEPR (Valence Shell Electron Pair Repulsion) theory, which predicts that electron groups around a central atom will arrange themselves to minimize repulsion. Lone pairs take up more space than bonding pairs, which affects the observed geometry.