Question

Choose the polar molecule from the following:

• A. \(CH_2=CH_2\)
• B. \(CHCl_3\)
• C. \(CCl_4\)
• D. \(CO_2\)

Answer 1

The Correct Option is B

To determine which molecule is polar, let's examine the molecular geometry and the distribution of electronegative atoms in each given option:

1. \(CH_2=CH_2\): This is ethylene. The molecule is symmetric, and the carbon atoms have no net dipole moment because they share electrons equally; hence this molecule is nonpolar.
2. \(CHCl_3\): This is chloroform. The molecule has a tetrahedral shape, and the three chlorine atoms, being more electronegative than hydrogen, create a net dipole moment. The asymmetrical arrangement of these electronegative atoms results in a polar molecule.
3. \(CCl_4\): This is carbon tetrachloride. Even though it contains polar C-Cl bonds, the molecule is symmetrical (tetrahedral), causing the dipoles to cancel out, making it nonpolar.
4. \(CO_2\): Carbon dioxide is a linear molecule where the dipole moments of the two C=O bonds are equal and opposite, cancelling each other out, making it nonpolar.

Therefore, the correct answer is \(CHCl_3\), as it is the only polar molecule in the list.

Answer 2

Among the given options, CHCl₃ (chloroform) is polar due to the asymmetrical arrangement of chlorine and hydrogen atoms around the central carbon, resulting in a net dipole moment. In contrast:

• CCl₄: Tetrahedral symmetry with four identical C-Cl bonds cancels out the dipole moments, making it non-polar.
• CO₂: Linear molecule with symmetrical C=O bonds cancels out dipole moments, making it non-polar.
• CH₂=CH₂: Ethene has a planar structure with symmetrical bonds, making it non-polar.

Thus, CHCl₃ is the only polar molecule.