Which of the following molecule /molecules will have zero dipole moment?

• H₂O
• CO₂
• CCl₄
• CHCl₃
• NH₃
• BF₃
• BeF₂

To determine which molecules have a zero dipole moment, we need to consider their molecular geometry and symmetry. A molecule will have a zero dipole moment if it is symmetrical, allowing the dipoles to cancel each other out.

Molecules with Zero Dipole Moment

• CO₂ (Carbon Dioxide): This molecule is linear, and the dipoles from the two C=O bonds cancel each other out.
• CCl₄ (Carbon Tetrachloride): This molecule has a tetrahedral shape, and the four C-Cl bonds are symmetrically arranged, resulting in no net dipole moment.
• BF₃ (Boron Trifluoride): With a trigonal planar structure, the three B-F bonds are evenly spaced, leading to a cancellation of dipoles.
• BeF₂ (Beryllium Fluoride): Similar to CO₂, BeF₂ is linear, and the dipoles cancel out due to symmetry.

Molecules with Non-Zero Dipole Moment

• H₂O (Water): This molecule has a bent shape, causing the dipoles to add up and create a net dipole moment.
• CHCl₃ (Chloroform): The asymmetrical arrangement of the C-H and C-Cl bonds results in a net dipole moment.
• NH₃ (Ammonia): Ammonia has a trigonal pyramidal shape, leading to a net dipole moment due to the lone pair on nitrogen.

In summary, the molecules that exhibit a zero dipole moment are CO₂, CCl₄, BF₃, and BeF₂.