Import Question JSON

A molecule has a zero dipole moment if it is symmetrical, meaning the individual bond dipoles cancel each other out. (i) $ \text{CO}_2 $: Carbon dioxide has a linear geometry ($ \text{O}=\text{C}=\text{O} $). The two $ \text{C}=\text{O} $ bond dipoles are equal in magnitude and opposite in direction, so they cancel out, resulting in a zero net dipole moment. (ii) $ \text{COCl}_2 $: Phosgene ($ \text{COCl}_2 $) has a trigonal planar geometry around the central carbon atom. However, due to the different electronegativities of oxygen and chlorine atoms, the bond dipoles are not symmetrically arranged and do not cancel out completely, leading to a non-zero dipole moment. (iii) $ \text{CH}_2\text{Cl}_2 $: Dichloromethane ($ \text{CH}_2\text{Cl}_2 $) has a tetrahedral geometry. The C-Cl bonds are polar, and the C-H bonds are also slightly polar. Due to the asymmetric arrangement of hydrogen and chlorine atoms, the individual bond dipoles do not cancel each other out, resulting in a non-zero dipole moment. (iv) $ \text{BCl}_3 $: Boron trichloride ($ \text{BCl}_3 $) has a trigonal planar geometry. The three B-Cl bond dipoles are equal in magnitude and are oriented at 120 degrees to each other. Their vector sum is zero, resulting in a zero net dipole moment. Therefore, the species with zero dipole moment are (i) $ \text{CO}_2 $ and (iv) $ \text{BCl}_3 $. The correct answer is option 1.