Which of the following correctly matches a compound with its molecular geometry?

• A. CO2 — linear
• B. BF3 — bent
• C. NH3 — tetrahedral
• D. CH4 — trigonal planar

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the concept of molecular geometry, which describes the three-dimensional arrangement of atoms in a molecule based on the positions of bonded atoms and lone pairs around the central atom.
2. Step 2: Recall the VSEPR (Valence Shell Electron Pair Repulsion) theory, which predicts molecular shapes by minimizing repulsions between electron pairs (bonding and lone pairs) around the central atom.
3. Step 3: Analyze each compound's central atom and its bonding/lone pairs to determine the correct geometry: - For CO\_2, the central carbon has two double bonds and no lone pairs, leading to a linear shape. - For BF\_3, the central boron has three bonding pairs and no lone pairs, resulting in a trigonal planar shape. - For NH\_3, the central nitrogen has three bonding pairs and one lone pair, giving a trigonal pyramidal shape. - For CH\_4, the central carbon has four bonding pairs and no lone pairs, resulting in a tetrahedral shape.
4. Step 4: Compare the given options with the correct geometries: - CO\_2 is linear (correct). - BF\_3 is trigonal planar, not bent. - NH\_3 is trigonal pyramidal, not tetrahedral. - CH\_4 is tetrahedral, not trigonal planar.
5. Step 5: Conclude that the only correct match from the list is CO\_2 — linear, and the other options are mismatched based on their molecular geometries.