Question

$\text{The total number of molecules with zero dipole moment among CH}_4, \text{ BF}_3, \text{ H}_2\text{O, HF, NH}_3, \text{ CO}_2 \text{ and} \\ \text{SO}_2 \text{ is \_\_\_\_\_\_\_\_.}$

Answer 1

Correct Answer: 3

To determine the number of molecules with zero dipole moment among the given set (CH₄, BF₃, H₂O, HF, NH₃, CO₂, SO₂), we analyze each molecule's structure and geometry.

CH₄: Tetrahedral geometry with symmetrical distribution of charge. Resultantly, it has a zero dipole moment.

BF₃: Trigonal planar geometry, symmetry in the molecule cancels out dipoles, resulting in a zero dipole moment.

H₂O: Bent geometry with a dipole moment due to the lone pairs on oxygen causing an asymmetric charge distribution.

HF: Linear molecule, but the difference in electronegativity induces a dipole moment.

NH₃: Trigonal pyramidal geometry with a net dipole moment due to the lone pair on nitrogen.

CO₂: Linear geometry; symmetrical opposite dipoles cancel out, resulting in a zero dipole moment.

SO₂: Bent geometry with a net dipole moment due to the asymmetric distribution of electrons.

Upon reviewing, CH₄, BF₃, and CO₂ have zero dipole moments. Therefore, the total number is 3.

Answer 2

Molecules with zero dipole moment are \( \text{CO}_2 \), \( \text{CH}_4 \), and \( \text{BF}_3 \).  

Thus, the total number of molecules with zero dipole moment is: 3.

The Correct Answer is: 3