Amongst BeF BF , H O, NH , CCl and HCl, the number of molecule with non-zero net dipole moment is __ — Chemical Bonding Chemistry Question

💡 Solution & Explanation

**Step 1: Identify the molecules and their structures** - BeF₂: Linear - BF₃: Trigonal planar - H₂O: Bent - NH₃: Trigonal pyramidal - CCl₄: Tetrahedral - HCl: Linear diatomic **Step 2: Determine polarity using the concept of dipole moment** A molecule has a net dipole moment when: - Individual bond dipoles exist AND - These dipoles do NOT cancel due to symmetry **Step 3: Analyze each molecule** - **BeF₂**: Linear, symmetric → dipoles cancel → μ = 0 - **BF₃**: Trigonal planar, symmetric → dipoles cancel → μ = 0 - **H₂O**: Bent, asymmetric → dipoles do NOT cancel → μ ≠ 0 ✓ - **NH₃**: Trigonal pyramidal, asymmetric → dipoles do NOT cancel → μ ≠ 0 ✓ - **CCl₄**: Tetrahedral, symmetric → dipoles cancel → μ = 0 - **HCl**: Diatomic with different atoms → μ ≠ 0 ✓ **Step 4: Count molecules with non-zero dipole moment** H₂O, NH₃, and HCl have non-zero net dipole moments. Therefore, the answer is 3.