Question

What is the molecular geometry of the water molecule (H₂O)?

• A. Linear
• B. Trigonal planar
• C. Bent
• D. Tetrahedral

Hint:

When determining molecular geometry, remember that lone pairs affect the shape. Water has a bent shape due to the presence of lone pairs on oxygen.

Answer 1

The Correct Option is C

Water (H₂O) is a simple molecule, but its geometry can be determined using VSEPR theory (Valence Shell Electron Pair Repulsion theory). Here’s how we analyze it:
1. Lewis Structure: - Oxygen has 6 valence electrons, and each hydrogen has 1 valence electron. In H₂O, oxygen forms two single bonds with hydrogen atoms, and it has two lone pairs of electrons remaining. 2. Electron Geometry: - The oxygen atom has 4 electron pairs around it: 2 bonding pairs (with H) and 2 lone pairs. According to VSEPR theory, these 4 electron pairs are arranged in a tetrahedral geometry to minimize repulsion. 3. Molecular Geometry: - However, the lone pairs are not visible in the molecule’s structure. The lone pairs cause the bonding pairs to repel each other, resulting in a bent molecular shape. - The bond angle between the hydrogen-oxygen-hydrogen atoms is approximately 104.5°, which is less than the ideal tetrahedral angle (109.5°) due to the lone pair repulsion. 4. Conclusion: - The molecular geometry of water is bent.