Choose the polar molecule from the following:

🧠 A molecule is polar if it has a non-zero net dipole moment — this requires both polar bonds AND an asymmetric arrangement so the bond dipoles do not cancel.

• $\ce{CCl4}$: 4 C–Cl bonds in tetrahedral arrangement → all 4 bond dipoles cancel → nonpolar ✗
• $\ce{CO2}$: 2 C=O bonds, linear → bond dipoles cancel → nonpolar ✗
• $\ce{CH2=CH2}$ (ethylene): planar symmetric molecule → net dipole = 0 → nonpolar ✗
• $\ce{CHCl3}$: 1 C–H + 3 C–Cl in tetrahedral arrangement. The 3 C–Cl dipoles point toward the Cl-rich end; the C–H dipole is weaker and in the opposite direction. Net dipole ≠ 0 → polar ✓

⚡ Key distinction: $\ce{CCl4}$ vs $\ce{CHCl3}$ — replacing one Cl with H breaks the symmetry and creates a net dipole.

$\boxed{\text{Answer: (d) } \ce{CHCl3}}$